Read raw resource of text

Create a raw resource of text, /res/raw/mytext.txt.

Hello!

It's a example of raw text in 
/res/raw/mytext.txt

Some text here:
Android is an operating system for mobile devices such as smartphones and tablet computers. It is developed by the Open Handset Alliance led by Google.

Java main code:

package com.AndroidTextResource;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

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

public class AndroidTextResourceActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);
        
        TextView myTextView = new TextView(this);
        setContentView(myTextView);
        

        InputStream inputStream = getResources().openRawResource(R.raw.mytext);
        
        ByteArrayOutputStream byteArrayOutputStream 
         = new ByteArrayOutputStream();
        
        String myText = "";
        int in;
  try {
   in = inputStream.read();
   while (in != -1)
         {
    byteArrayOutputStream.write(in);
          in = inputStream.read();
         }
   inputStream.close();
   myText = byteArrayOutputStream.toString();
  }catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

        myTextView.setText(myText);
    }
}

- Read raw text file, and display in ScrollView.

Using shape to define round drawable

To define our shape as a drawable, create XML(s) under /res/drawable/ folder.

/res/drawable/redroundrect.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android">
 <solid 
  android:color="#FFFF0000"/>
 <corners 
  android:radius="15dp" />
 <padding 
  android:left="20dp" 
  android:top="20dp" 
  android:right="20dp" 
  android:bottom="2dp" />
</shape>

/res/drawable/greenroundrect.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android">
 <solid 
  android:color="#FF00FF00"/>
 <corners 
  android:radius="15dp" />
 <padding 
  android:left="20dp" 
  android:top="20dp" 
  android:right="20dp" 
  android:bottom="2dp" />
</shape>

/res/drawable/blueroundrect.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android">
 <solid 
  android:color="#FF0000FF"/>
 <corners 
  android:radius="15dp" />
 <padding 
  android:left="20dp" 
  android:top="20dp" 
  android:right="20dp" 
  android:bottom="2dp" />
</shape>

Using it inside 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"
    />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="RED in XML"
    android:background="@drawable/redroundrect" />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="GREEN in XML"
    android:background="@drawable/greenroundrect" />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="BLUE in XML"
    android:background="@drawable/blueroundrect" />
<TextView  
    android:id="@+id/javared"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="RED using Java"/>
<TextView  
    android:id="@+id/javagreen"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="GREEN using Java"/>
<TextView  
    android:id="@+id/javablue"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="BLUE using Java"/>
</LinearLayout>

In Java code

package com.AndroidTestResources;

import android.app.Activity;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.os.Bundle;
import android.widget.TextView;

public class AndroidTestResourcesActivity extends Activity {
 
 TextView javaRed, javaGreen, javaBlue;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        javaRed = (TextView)findViewById(R.id.javared);
        javaGreen = (TextView)findViewById(R.id.javagreen);
        javaBlue = (TextView)findViewById(R.id.javablue);
        
        Drawable redRoundRect 
        = getResources().getDrawable(R.drawable.redroundrect);
        Drawable greenRoundRect 
        = getResources().getDrawable(R.drawable.greenroundrect);
        Drawable blueRoundRect 
        = getResources().getDrawable(R.drawable.blueroundrect);
        
        javaRed.setBackgroundDrawable(redRoundRect);
        javaGreen.setBackgroundDrawable(greenRoundRect);
        javaBlue.setBackgroundDrawable(blueRoundRect);
    }
}

Related: Define color drawable in XML

Define color drawable in XML

We can define our custom color in XML under /res/values/ folder.

example: /res/values/myresources.xml

<resources>
 <drawable name="red_color">#ff0000</drawable>
 <drawable name="blue_color">#0000ff</drawable>
 <drawable name="green_color">#00ff00</drawable>
</resources>

After color defined, it can be acccessed as drawable in XML or using Java code.

<?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:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="RED in XML"
    android:background="@drawable/red_color" />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="GREEN in XML"
    android:background="@drawable/green_color" />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="BLUE in XML"
    android:background="@drawable/blue_color" />
<TextView  
    android:id="@+id/javared"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="RED using Java"/>
<TextView  
    android:id="@+id/javagreen"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="GREEN using Java"/>
<TextView  
    android:id="@+id/javablue"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="BLUE using Java"/>
</LinearLayout>

package com.AndroidTestResources;

import android.app.Activity;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.widget.TextView;

public class AndroidTestResourcesActivity extends Activity {
 
 TextView javaRed, javaGreen, javaBlue;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        javaRed = (TextView)findViewById(R.id.javared);
        javaGreen = (TextView)findViewById(R.id.javagreen);
        javaBlue = (TextView)findViewById(R.id.javablue);
        
        ColorDrawable red = (ColorDrawable)getResources().getDrawable(R.drawable.red_color);
        ColorDrawable green = (ColorDrawable)getResources().getDrawable(R.drawable.green_color);
        ColorDrawable blue = (ColorDrawable)getResources().getDrawable(R.drawable.blue_color);
        
        javaRed.setBackgroundDrawable(red);
        javaGreen.setBackgroundDrawable(green);
        javaBlue.setBackgroundDrawable(blue);
    }
}

Related: Using shape to define round drawable

Using Android device build-in light sensor

It's a simple light meter Using Android device build-in light sensor. A ProgressBar is defined in main.xml as a indicator of the light sensor. The default value of 100 defined in android:max is a dummy value, it will be updated after lightSensor.getMaximumRange(). The updated reading will be be read in lightSensorEventListener, and update the ProgressBar accordingly.

package com.AndroidLightSensor;

import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidLightSensorActivity extends Activity {
 
 ProgressBar lightMeter;
 TextView textMax, textReading;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        lightMeter = (ProgressBar)findViewById(R.id.lightmeter);
        textMax = (TextView)findViewById(R.id.max);
        textReading = (TextView)findViewById(R.id.reading);
        
        SensorManager sensorManager 
        = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
        Sensor lightSensor 
        = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
     
        if (lightSensor == null){
         Toast.makeText(AndroidLightSensorActivity.this, 
           "No Light Sensor! quit-", 
           Toast.LENGTH_LONG).show();
        }else{
         float max =  lightSensor.getMaximumRange();
         lightMeter.setMax((int)max);
         textMax.setText("Max Reading: " + String.valueOf(max));
         
         sensorManager.registerListener(lightSensorEventListener, 
           lightSensor, 
           SensorManager.SENSOR_DELAY_NORMAL);
         
        }
    }
    
    SensorEventListener lightSensorEventListener
    = new SensorEventListener(){

  @Override
  public void onAccuracyChanged(Sensor sensor, int accuracy) {
   // TODO Auto-generated method stub
   
  }

  @Override
  public void onSensorChanged(SensorEvent event) {
   // TODO Auto-generated method stub
   if(event.sensor.getType()==Sensor.TYPE_LIGHT){
    float currentReading = event.values[0];
    lightMeter.setProgress((int)currentReading);
    textReading.setText("Current Reading: " + String.valueOf(currentReading));
   }
  }
     
    };
}

<?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"
    />
<ProgressBar
    android:id="@+id/lightmeter"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:padding="20dp"
    style="?android:attr/progressBarStyleHorizontal"
    android:max="100"
    android:progress="0"
    />
<TextView  
    android:id="@+id/max"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    />
<TextView  
    android:id="@+id/reading"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    />
</LinearLayout>

Start Battery use checking using Intent.ACTION_POWER_USAGE_SUMMARY

package com.AndroidBatteryUsage;

import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Bundle;
import android.widget.Toast;

public class AndroidBatteryUsageActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        PackageManager packageManager = getPackageManager();
        Intent intent = new Intent(Intent.ACTION_POWER_USAGE_SUMMARY);
        ResolveInfo resolveInfo = packageManager.resolveActivity(intent, 0);
        
        if(resolveInfo == null){
         Toast.makeText(AndroidBatteryUsageActivity.this, 
           "No suitable Activity found!", 
           Toast.LENGTH_LONG).show(); 
        }else{
         startActivity(intent);
        }
    }
}