Comment définir la ressource de couleur comme fond d'écran dans Android?

Question

Je veux définir une couleur solide comme fond d'écran dans Android, mais quand je clique sur le bouton, l'application s'arrête malheureusement.

Voici mon code:

protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    Button btn = (Button) findViewById(R.id.btn); 
    btn.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      WallpaperManager wm = WallpaperManager.getInstance(getApplicationContext()); 
      try { 
       wm.setResource(R.color.red); 
       Toast.makeText(getApplicationContext(), "Wallpaper changed", Toast.LENGTH_LONG).show(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 
     } 
    }); 
} 

Voici le code de Colors.xml:

<?xml version="1.0" encoding="utf-8"?> 
<resources> 
    <color name="red">#ff4366</color> 
</resources> 

Logcat:

10-24 15:59:26.216 12529-12529/com.danish.testapp D/AndroidRuntime﹕ Shutting down VM 
    --------- beginning of crash 
10-24 15:59:26.216 12529-12529/com.danish.testapp E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    Process: com.danish.testapp, PID: 12529 
    java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String java.lang.CharSequence.toString()' on a null object reference 
      at android.content.res.Resources.openRawResource(Resources.java:1271) 
      at android.content.res.Resources.openRawResource(Resources.java:1241) 
      at android.app.WallpaperManager.setResource(WallpaperManager.java:739) 
      at com.danish.testapp.MainActivity$1.onClick(MainActivity.java:30) 
      at android.view.View.performClick(View.java:5198) 
      at android.view.View$PerformClick.run(View.java:21147) 
      at android.os.Handler.handleCallback(Handler.java:739) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:148) 
      at android.app.ActivityThread.main(ActivityThread.java:5417) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

J'ai également défini les autorisations requises dans le manifeste.

Answer 1

Pour WallpaperManager, vous devez définir l'élément dessinable.

wm.setResource(R.drawable.your_drawable); 

Edité

aussi vous devez définir l'autorisation.

android.permission.SET_WALLPAPER 

pour la couleur de jeu avec drawable vous pouvez en utilisant

<?xml version="1.0" encoding="utf-8"?> 
<selector xmlns:android="http://schemas.android.com/apk/res/android"> 

    <item> 
     <shape> 
      <solid android:color="@color/your_coloe" /> 
     </shape> 
    </item> 

</selector> 

Edité

Enfin résolu:

I Rédaction d'un échantillon. ça a marché. Profitez-en.

public class MainActivity extends AppCompatActivity { 

    private static final int REQUEST_CODE = 1; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     WallpaperManager wm = WallpaperManager.getInstance(this); 

     Drawable drawable = getResources().getDrawable(R.drawable.mydrawable); 
     Bitmap bitmap = drawableToBitmap(drawable); 
     Log.i(getClass().getName(), "bitmap = " +bitmap); 
     try { 
      wm.setBitmap(bitmap); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     Toast.makeText(this, "Wallpaper changed", 
       Toast.LENGTH_LONG).show(); 



    } 



    public static Bitmap drawableToBitmap (Drawable drawable) { 
     Bitmap bitmap = null; 

     if (drawable instanceof BitmapDrawable) { 
      BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable; 
      if(bitmapDrawable.getBitmap() != null) { 
       return bitmapDrawable.getBitmap(); 
      } 
     } 

     if(drawable.getIntrinsicWidth() <= 0 || drawable.getIntrinsicHeight() <= 0) { 
      bitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888); // Single color bitmap will be created of 1x1 pixel 
     } else { 
      bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888); 
     } 

     Canvas canvas = new Canvas(bitmap); 
     drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight()); 
     drawable.draw(canvas); 
     return bitmap; 
    } 
}