Detect Multi-Touch Event

It's a testing app for multi-touch event, target API level 8, Android 2.2. In my test on Nexus One running 2.2.1, only two points can be recognized.

package com.TestMultiTouch;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

public class TestMultiTouch extends Activity {
 
 //In this test, handle maximum of 2 pointer
 final int MAX_POINT_CNT = 2;
 
 String[] pointerAction = new String[MAX_POINT_CNT];
 float[] x = new float[MAX_POINT_CNT];
 float[] y = new float[MAX_POINT_CNT];
 TextView currentPointer;
 TextView pointerStatus_01, pointerStatus_02;
 TextView textDistance;
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       LinearLayout MainLayout = (LinearLayout)findViewById(R.id.mainlayout);
       MainLayout.setOnTouchListener(OnTouchListener);
      
       currentPointer = (TextView)findViewById(R.id.currentpointer);
       pointerStatus_01 = (TextView)findViewById(R.id.pointstatus_01);
       pointerStatus_02 = (TextView)findViewById(R.id.pointstatus_02);
       textDistance = (TextView)findViewById(R.id.distance);
   }

   private View.OnTouchListener OnTouchListener
   = new View.OnTouchListener(){

  @Override
  public boolean onTouch(View view, MotionEvent motionEvent) {
   // TODO Auto-generated method stub
   
   int pointerIndex = ((motionEvent.getAction() & MotionEvent.ACTION_POINTER_ID_MASK)
     >> MotionEvent.ACTION_POINTER_ID_SHIFT);
   int pointerId = motionEvent.getPointerId(pointerIndex);
   int action = (motionEvent.getAction() & MotionEvent.ACTION_MASK);
   int pointCnt = motionEvent.getPointerCount();
   
   if (pointCnt <= MAX_POINT_CNT){
    if (pointerIndex <= MAX_POINT_CNT - 1){

     for (int i = 0; i < pointCnt; i++) {
      int id = motionEvent.getPointerId(i);
      x[id] = (int)motionEvent.getX(i);
      y[id] = (int)motionEvent.getY(i);
      }
     
     switch (action){
     case MotionEvent.ACTION_DOWN:
      pointerAction[pointerId] = "ACTION_DOWN";
      break;
     case MotionEvent.ACTION_POINTER_DOWN:
      pointerAction[pointerId] = "ACTION_POINTER_DOWN";
      break;
     case MotionEvent.ACTION_MOVE:
      pointerAction[pointerId] = "ACTION_MOVE";
      
      int distance = (int) Math.sqrt(
        (x[0] - x[1]) * (x[0] - x[1]) +
        (y[0] - y[1]) * (y[0] - y[1]));
      textDistance.setText("distance: " + String.valueOf(distance));
      
      break;
     case MotionEvent.ACTION_UP:
      pointerAction[pointerId] = "ACTION_UP";
      break;
     case MotionEvent.ACTION_POINTER_UP:
      pointerAction[pointerId] = "ACTION_POINTER_UP";
      break;
     case MotionEvent.ACTION_CANCEL:
      pointerAction[pointerId] = "ACTION_CANCEL";
      break;
     default:
      pointerAction[pointerId] = "Unknown!";
     }

     currentPointer.setText(
       "action = " + pointerAction[pointerId] + "\n"
       + "pointerIndex = " + String.valueOf(pointerIndex) + "\n"
       + "pointerId = " + String.valueOf(pointerId) + "\n"
       + "getPointerCount() = " + motionEvent.getPointerCount() + "\n");
     
        pointerStatus_01.setText("[0] : "
          + String.valueOf(x[0]) + " : "
          + String.valueOf(y[0]));
        
        pointerStatus_02.setText("[1] : "
          + String.valueOf(x[1]) + " : "
          + String.valueOf(y[1]));
    }
   }
   
   return true; //means event have been processed
  }};
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:id="@+id/mainlayout"
   >
<TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<TextView 
   android:id="@+id/currentpointer"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/pointstatus_01"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/pointstatus_02"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/distance"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
</LinearLayout>

Refer Android Document for more details about android.view.MotionEvent

Related Post:
- Detect Touch Event
- Detect Touch Event, test on Custom View
- Detect Multi-Touch Event, test on Custom View

Detect Touch Event, test on Custom View

package com.TestSingleTouch;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;

public class TestSingleTouch extends Activity {

public class TouchView extends View {

 private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
 private float x, y;
 boolean touching = false;

public TouchView(Context context) {
 super(context);
 // TODO Auto-generated constructor stub
}

@Override
protected void onDraw(Canvas canvas) {
 // TODO Auto-generated method stub
 if(touching){
  paint.setStyle(Paint.Style.STROKE);
  paint.setStrokeWidth(1);
  paint.setColor(Color.WHITE);
  canvas.drawCircle(x, y, 50f, paint);
 }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 // TODO Auto-generated method stub
 setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec),
       MeasureSpec.getSize(heightMeasureSpec));
}

@Override
public boolean onTouchEvent(MotionEvent event) {
 // TODO Auto-generated method stub

 int action = event.getAction();
 switch(action){
 case MotionEvent.ACTION_MOVE:
  x = event.getX();
  y = event.getY();
  touching = true;
  break;
 case MotionEvent.ACTION_DOWN:
  x = event.getX();
  y = event.getY();
  touching = true;
  break;
 case MotionEvent.ACTION_UP:
  touching = false;
  break;
 default:
  touching = false;
 }
 invalidate();
 return true;
}

}

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(new TouchView(this));

}

}

Related Post:
- Detect Touch Event, test on Custom View; part II
- Detect Touch Event
- Detect Multi-Touch Event
- Detect Multi-Touch Event, test on Custom View

- Touch to move Bitmap inside a custom View

Detect Touch Event

package com.TestSingleTouch;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

public class TestSingleTouch extends Activity {

TextView textEvent, textX, textY;

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       LinearLayout MainLayout = (LinearLayout)findViewById(R.id.mainlayout);
       textEvent = (TextView)findViewById(R.id.event);
       textX = (TextView)findViewById(R.id.x);
       textY = (TextView)findViewById(R.id.y);
      
       MainLayout.setOnTouchListener(OnTouchListener);
   }
  
   private View.OnTouchListener OnTouchListener
   = new View.OnTouchListener(){

 @Override
 public boolean onTouch(View view, MotionEvent motionEvent) {
  // TODO Auto-generated method stub
 
  textX.setText("x: " + String.valueOf(motionEvent.getX()));
  textY.setText("y: " + String.valueOf(motionEvent.getY()));
 
  int action = motionEvent.getAction();
 
  switch (action){
  case MotionEvent.ACTION_DOWN:
   textEvent.setText("ACTION_DOWN");
   break;
  case MotionEvent.ACTION_MOVE:
   textEvent.setText("ACTION_MOVE");
   break;
  case MotionEvent.ACTION_UP:
   textEvent.setText("ACTION_UP");
   break;
  case MotionEvent.ACTION_CANCEL:
   textEvent.setText("ACTION_CANCEL");
   break;
  default:
   textEvent.setText("Unknown!");
  }

  return true; //means event have been processed
 }
   
   };
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:id="@+id/mainlayout"
   >
<TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<TextView 
   android:id="@+id/event"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/x"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/y"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
</LinearLayout>

Related Post:
- Detect Touch Event, test on Custom View
- Detect Multi-Touch Event
- Detect Multi-Touch Event, test on Custom View

Set EditText horizontally scrollable

It can be define in XML using the statement:

 android:scrollHorizontally="true"

or using Java code:

 setHorizontallyScrolling(true);

Create custom dialog with EditText

Create a XML in /res/layout/ folder to define the layout of the custom dialog.
eg. customlayout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/customdialog"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dp"
>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/icon"
/>
<TextView
android:id="@+id/dialogtextview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<EditText
android:id="@+id/dialogedittext"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/dialogupdate"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Update"
/>
<Button
android:id="@+id/dialogdismiss"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Dismiss"
/>
</LinearLayout>

Java code, eg. AndroidCustomDialog.java

package com.AndroidCustomDialog;

import android.app.Activity;
import android.app.Dialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class AndroidCustomDialog extends Activity {

static final int CUSTOM_DIALOG_ID = 0;

TextView customDialog_TextView;
EditText customDialog_EditText;
Button customDialog_Update, customDialog_Dismiss;
;

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       Button buttonStartDialog = (Button)findViewById(R.id.startdialog);
       buttonStartDialog.setOnClickListener(new Button.OnClickListener(){

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   showDialog(CUSTOM_DIALOG_ID);
  }
       });
   }
  
   private Button.OnClickListener customDialog_UpdateOnClickListener
   = new Button.OnClickListener(){

 @Override
 public void onClick(View arg0) {
  // TODO Auto-generated method stub
  customDialog_TextView.setText(customDialog_EditText.getText().toString());
 }
   
   };
  
   private Button.OnClickListener customDialog_DismissOnClickListener
   = new Button.OnClickListener(){

 @Override
 public void onClick(View arg0) {
  // TODO Auto-generated method stub
  dismissDialog(CUSTOM_DIALOG_ID);
 }
   
   };
  
@Override
protected Dialog onCreateDialog(int id) {
 // TODO Auto-generated method stub
 Dialog dialog = null;;
    switch(id) {
    case CUSTOM_DIALOG_ID:
     dialog = new Dialog(AndroidCustomDialog.this);

     dialog.setContentView(R.layout.customlayout);
     dialog.setTitle("Custom Dialog");
    
     customDialog_EditText = (EditText)dialog.findViewById(R.id.dialogedittext);
     customDialog_TextView = (TextView)dialog.findViewById(R.id.dialogtextview);
     customDialog_Update = (Button)dialog.findViewById(R.id.dialogupdate);
     customDialog_Dismiss = (Button)dialog.findViewById(R.id.dialogdismiss);
    
     customDialog_Update.setOnClickListener(customDialog_UpdateOnClickListener);
     customDialog_Dismiss.setOnClickListener(customDialog_DismissOnClickListener);
    
        break;
    }
    return dialog;
}  
}

main.xml, simple with a button to start the custom dialog.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   >
<TextView
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<Button
   android:id="@+id/startdialog"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text=" Start Dialog "
   />
</LinearLayout>

Please notice that the call-back function onCreateDialog() will be called when a dialog is requested for the first time, such that the content defined in onCreateDialog() will not be updated next time.

If you have some dynamic content changed in runtime, you can override the call-back method onPrepareDialog(), it will be called every time a dialog is opened. Override this method if you want to change any properties of the dialog each time it is opened. Refer to the post: Create custom dialog with dynamic content, updated in onPrepareDialog().

Next:
- Pass back data from dialog to activity

Create Dialog with options, using AlertDialog.Builder

package com.AndroidAlertDialog;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class AndroidAlertDialog extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        Button buttonStartDialog = (Button)findViewById(R.id.startdialog);
        buttonStartDialog.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    StartDialog();
   }});
    }
    
    private void StartDialog(){
     AlertDialog.Builder myAlertDialog = new AlertDialog.Builder(this);
     myAlertDialog.setTitle("My Alert Dialog");
     myAlertDialog.setMessage("It provide options for user to select");
     myAlertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
       
            // do something when the button is clicked
            public void onClick(DialogInterface arg0, int arg1) {
                Toast.makeText(getApplicationContext(), "'Yes' button clicked", Toast.LENGTH_LONG).show();
            }
        });
     myAlertDialog.setNeutralButton("Option 1", new DialogInterface.OnClickListener() {
      
            // do something when the button is clicked
            public void onClick(DialogInterface arg0, int arg1) {
                Toast.makeText(getApplicationContext(), "'Option 1' button clicked", Toast.LENGTH_LONG).show();
            }
        });
     myAlertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
      
            // do something when the button is clicked
            public void onClick(DialogInterface arg0, int arg1) {
                Toast.makeText(getApplicationContext(), "'No' button clicked", Toast.LENGTH_LONG).show();
            }
        });
     myAlertDialog.show();
    }
}

TimePickerDialog - how to set 24 hour view, or AM/PM.

TimePickerDialog is a dialog that prompts the user for the time of day using a TimePicker. Refer the post "TimePickerDialog" for working example.



TimePickerDialog provide two Constructors:

TimePickerDialog(Context context, TimePickerDialog.OnTimeSetListener callBack, int hourOfDay, int minute, boolean is24HourView)

TimePickerDialog(Context context, int theme, TimePickerDialog.OnTimeSetListener callBack, int hourOfDay, int minute, boolean is24HourView)

In both version of the Constructors, the last parameter, boolean is24HourView, define whether this is a 24 hour view, or AM/PM.

To select 24 hour view, set it true.
To select AM/PM view, set it false.

AutoCompleteTextView

AutoCompleteTextView is an editable text view that shows completion suggestions automatically while the user is typing. The list of suggestions is displayed in a drop down menu from which the user can choose an item to replace the content of the edit box with.

Ex.


create a xml file, /res/values/myvalues.xml, to hold the suggestions.

<?xml version="1.0" encoding="UTF-8"?>
<resources>
<array name="month">
       <item>January</item>
       <item>February</item>
       <item>March</item>
       <item>April</item>
       <item>May</item>
       <item>June</item>
       <item>July</item>
       <item>August</item>
       <item>September</item>
       <item>October</item>
       <item>November</item>
       <item>December</item>
</array>
</resources>

Main Java code

package com.ExAutoCompleteTextView;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;

public class ExAutoCompleteTextView extends Activity implements TextWatcher {
 
 AutoCompleteTextView autoCompleteTextView;
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main); 
       autoCompleteTextView = (AutoCompleteTextView)findViewById(R.id.input);
       String[] month = getResources().getStringArray(R.array.month);
       autoCompleteTextView.addTextChangedListener(this); 
       autoCompleteTextView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, month)); 
   }

 @Override
 public void afterTextChanged(Editable arg0) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
   int arg3) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
  // TODO Auto-generated method stub
  
 }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   >
<TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<AutoCompleteTextView
   android:id="@+id/input" 
   android:layout_width="fill_parent" 
   android:layout_height="wrap_content" 
   android:completionThreshold="1" 
   />
</LinearLayout>

Load Array from XML Resources

To load array contents from XML resources:

 String[] month = getResources().getStringArray(R.array.xxx);

where xxx is the name of the array.

Here is a example of ListActivity, using ArrayAdapter<String> with array contents loaded from XML resources.

create a xml file, /res/values/myvalues.xml

<?xml version="1.0" encoding="UTF-8"?>
<resources>
<array name="month">
        <item>January</item>
        <item>February</item>
        <item>March</item>
        <item>April</item>
        <item>May</item>
        <item>June</item>
        <item>July</item>
        <item>August</item>
        <item>September</item>
        <item>October</item>
        <item>November</item>
        <item>December</item>
</array>
</resources>

package com.ExMyList;

import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;

public class ExMyList extends ListActivity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
       
        String[] month = getResources().getStringArray(R.array.month);
        setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, month));
    }
}

ViewFlipper with Animation

ViewFlipper is a simple ViewAnimator that will animate between two or more views that have been added to it. Only one child is shown at a time. If requested, can automatically flip between each child at a regular interval.





create four XML file for the animation in /res/anim folder

/res/anim/flipinnext.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
   android:interpolator="@android:anim/decelerate_interpolator">
<translate
   android:fromXDelta="-100%"
   android:toXDelta="0%"
   android:duration="500" />
</set>

/res/anim/flipoutnext.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
   android:interpolator="@android:anim/decelerate_interpolator">
<translate
   android:fromXDelta="0%"
   android:toXDelta="100%"
   android:duration="500" />
</set>

/res/anim/flipinprevious.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
   android:interpolator="@android:anim/decelerate_interpolator">
<translate
   android:fromXDelta="100%"
   android:toXDelta="0%"
   android:duration="500" />
</set>

/res/anim/flipoutprevious.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
   android:interpolator="@android:anim/decelerate_interpolator">
<translate
   android:fromXDelta="0%"
   android:toXDelta="-100%"
   android:duration="500" />
</set>

/res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   >
<TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<Button
   android:id="@+id/flipnext"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Flip Next"
   />
<Button
   android:id="@+id/flipprevious"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Flip Previous"
   />
<ViewFlipper
   android:id="@+id/viewflipper"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">
<LinearLayout
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:orientation="vertical">
<TextView
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="First Screen"/>
<ImageView
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:src="@drawable/icon"/>
</LinearLayout>
<LinearLayout
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:orientation="vertical">
<TextView
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Second Screen"/>
<Button
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:text="Big Big Button"/>
</LinearLayout>
<LinearLayout
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:orientation="vertical">
<TextView
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Third Screen"/>
<Button
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Normal Button"/>
<Button
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Normal Button"/>
<Button
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Normal Button"/>
</LinearLayout>
</ViewFlipper>
</LinearLayout>

main java code

package com.MyViewFlipper;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ViewFlipper;

public class MyViewFlipper extends Activity {

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       Button buttonFlipNext = (Button)findViewById(R.id.flipnext);
       Button buttonFlipPrevious = (Button)findViewById(R.id.flipprevious);
      
       final ViewFlipper viewFlipper = (ViewFlipper)findViewById(R.id.viewflipper);
       final Animation animFlipInNext = AnimationUtils.loadAnimation(this, R.anim.flipinnext);
       final Animation animFlipOutNext = AnimationUtils.loadAnimation(this, R.anim.flipoutnext);
       final Animation animFlipInPrevious = AnimationUtils.loadAnimation(this, R.anim.flipinprevious);
       final Animation animFlipOutPrevious = AnimationUtils.loadAnimation(this, R.anim.flipoutprevious);
      
       buttonFlipNext.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    viewFlipper.setInAnimation(animFlipInNext);
          viewFlipper.setOutAnimation(animFlipOutNext);
    viewFlipper.showNext();
   }});
      
       buttonFlipPrevious.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    viewFlipper.setInAnimation(animFlipInPrevious);
          viewFlipper.setOutAnimation(animFlipOutPrevious);
    viewFlipper.showPrevious();
   }});
   }
}

Example to implement SlidingDrawer in XML

SlidingDrawer hides content out of the screen and allows the user to drag a handle to bring the content on screen.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<SlidingDrawer
     android:id="@+id/drawer"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:orientation="vertical"
     android:handle="@+id/handle"
     android:content="@+id/content">
<ImageView 
     android:id="@id/handle"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content" 
     android:src="@drawable/icon"/>
<LinearLayout
     android:id="@id/content"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:orientation="vertical">
<Button
     android:layout_width="fill_parent"
     android:layout_height="fill_parent" 
     android:text="Big Big Button"/>
</LinearLayout>
     
</SlidingDrawer>
</LinearLayout>

getExternalStoragePublicDirectory(String type): Get a top-level public external storage directory for particular type

Start from API Level 8 (Android 2.2), android.os.Environment class provide getExternalStoragePublicDirectory(String type) method, to get a top-level public external storage directory for placing files of a particular type. This is where the user will typically place and manage their own files, so you should be careful about what you put here to ensure you don't erase their files or get in the way of their own organization.

package com.AndroidExternalStoragePublicDirectory;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.TextView;

public class AndroidExternalStoragePublicDirectory extends Activity {
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       TextView textDIRECTORY_MUSIC = (TextView)findViewById(R.id.textDIRECTORY_MUSIC);
       TextView textDIRECTORY_PODCASTS = (TextView)findViewById(R.id.textDIRECTORY_PODCASTS);
       TextView textDIRECTORY_RINGTONES = (TextView)findViewById(R.id.textDIRECTORY_RINGTONES);
       TextView textDIRECTORY_ALARMS = (TextView)findViewById(R.id.textDIRECTORY_ALARMS);
       TextView textDIRECTORY_NOTIFICATIONS = (TextView)findViewById(R.id.textDIRECTORY_NOTIFICATIONS);
       TextView textDIRECTORY_PICTURES = (TextView)findViewById(R.id.textDIRECTORY_PICTURES);
       TextView textDIRECTORY_MOVIES = (TextView)findViewById(R.id.textDIRECTORY_MOVIES);
       TextView textDIRECTORY_DOWNLOADS = (TextView)findViewById(R.id.textDIRECTORY_DOWNLOADS);
       TextView textDIRECTORY_DCIM = (TextView)findViewById(R.id.textDIRECTORY_DCIM);
      
      
       textDIRECTORY_MUSIC.setText(
         "DIRECTORY_MUSIC: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC)
         .getPath());
      
       textDIRECTORY_PODCASTS.setText(
         "DIRECTORY_PODCASTS: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PODCASTS)
         .getPath());
       textDIRECTORY_RINGTONES.setText(
         "DIRECTORY_RINGTONES: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_RINGTONES)
         .getPath());
       textDIRECTORY_ALARMS.setText(
         "DIRECTORY_ALARMS: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_ALARMS)
         .getPath());
       textDIRECTORY_NOTIFICATIONS.setText(
         "DIRECTORY_NOTIFICATIONS: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_NOTIFICATIONS)
         .getPath());
       textDIRECTORY_PICTURES.setText(
         "DIRECTORY_PICTURES: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES)
         .getPath());
       textDIRECTORY_MOVIES.setText(
         "DIRECTORY_MOVIES: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES)
         .getPath());
       textDIRECTORY_DOWNLOADS.setText(
         "DIRECTORY_DOWNLOADS: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)
         .getPath());
       textDIRECTORY_DCIM.setText(
         "DIRECTORY_DCIM: " +
         Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM)
         .getPath());
   }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   >
<TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<TextView 
   android:id="@+id/textDIRECTORY_MUSIC"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_PODCASTS"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_RINGTONES"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_ALARMS"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_NOTIFICATIONS"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_PICTURES"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_MOVIES"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_DOWNLOADS"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
<TextView 
   android:id="@+id/textDIRECTORY_DCIM"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   />
</LinearLayout>

Detect GPS ON/OFF status using android.provider.Settings.Secure

android.provider.Settings.Secure is secure system settings, containing system preferences that applications can read but are not allowed to write. These are for preferences that the user must explicitly modify through the system UI or specialized APIs for those values, not modified directly by applications.

Start from API level 8, Android 2.2, Settings.Secure.isLocationProviderEnabled() is added as helper method for determining if a location provider is enabled.

package com.AndroidGPS;

import android.app.Activity;
import android.content.ContentResolver;
import android.location.LocationManager;
import android.os.Bundle;
import android.provider.Settings;
import android.widget.TextView;

public class AndroidGPS extends Activity {

TextView textGpsStatus;

  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      textGpsStatus = (TextView)findViewById(R.id.gpsstatus);

  }

  @Override
protected void onResume() {
 // TODO Auto-generated method stub
 super.onResume();
 displayGpsStatus();
}

private void displayGpsStatus(){
   ContentResolver contentResolver = getBaseContext().getContentResolver();
      boolean gpsStatus = Settings.Secure.isLocationProviderEnabled(contentResolver, LocationManager.GPS_PROVIDER);
      if(gpsStatus){
       textGpsStatus.setText("GPS: ON");
      }else{
       textGpsStatus.setText("GPS: OFF");
      }
  }
}

Remark:
Another method setLocationProviderEnabled() is also provided to enable or disable a single location provider. But up to this writing, I can't make it work! Also, according to Settings.Secure document, secure system settings can be read by applications but cannot be write. I don't know what is the purpose of the method setLocationProviderEnabled()!

Related:
- How to check if GPS is currently enabled or disabled
- Start Location setting if GPS disabled

How to set orientation of activity/application in AndroidManifest.xml

To set orientation in AndroidManifest.xml, add the following code under <activity> or <application>.

 android:screenOrientation="landscape"

Related: Change the desired orientation of activity: setRequestedOrientation()

How to send SMS using android.telephony.SmsManager

android.telephony.SmsManager manages SMS operations such as sending data, text, and pdu SMS messages. Get this object by calling the static method SmsManager.getDefault(). It supports both GSM and CDMA; please don't mix up with deprecated android.telephony.gsm.SmsManager.

  SmsManager MySmsManager = SmsManager.getDefault();
 String PhoneNumber = "123....67"; //fil with the receiver's phone number
 String SMSText = "Hello Android";
 MySmsManager.sendTextMessage(PhoneNumber, null, SMSText, null, null);

Get ANDROID_ID

ANDROID_ID is 64-bit number (as a hex string) that is randomly generated on the device's first boot and should remain constant for the lifetime of the device. (The value may change if a factory reset is performed on the device.)

 String Id = Settings.Secure.getString(getContentResolver(), Settings.Secure.ANDROID_ID);

Related Post:
- Get phone type using android.telephony.TelephonyManager

Check and Gets the Android external storage directory

The class android.os.Environment provides access to environment variables.

The method getExternalStorageDirectory() can be used to get the Android external storage directory. This directory may not currently be accessible if it has been mounted by the user on their computer, has been removed from the device, or some other problem has happened. You can determine its current state with getExternalStorageState().

        TextView textInfo = (TextView)findViewById(R.id.info);
      
       String stringInfo;
       String state = Environment.getExternalStorageState();
       if(state.equals(Environment.MEDIA_MOUNTED)){
        stringInfo = "Media Mounted:\n"
         + Environment.getExternalStorageDirectory().getPath();
       }else if(state.equals(Environment.MEDIA_MOUNTED_READ_ONLY)){
        stringInfo = "Media (Read Only) Mounted:\n"
         + Environment.getExternalStorageDirectory().getPath();
       }else{
        stringInfo = "No Media Mounted!\n";
       }
      
       textInfo.setText(stringInfo);

How to get application context

To get the context, the method Context.getApplicationContext() or Activity.getApplication() can be used.

        
        textContext1.setText("using getApplicationContext():\n" + getApplicationContext());
        textContext2.setText("using getApplication():\n" + getApplication());