Question

我有一个TextureView用于绘制一些lines和rect以及我需要的抽奖但是当我通过单击主页按钮退出应用程序并返回应用程序时 TextureView一直是黑色的，当我再次调用draw方法时，它现在显示任何只有黑色的东西（只有TextureView黑色而不是屏幕）

所以首先这是我的Manifest

 <application
    android:hardwareAccelerated="true"
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/MyMaterialTheme" >



    <activity android:name=".activity.MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

现在我的TextureView

public class CanvasView extends TextureView implements   TextureView.SurfaceTextureListener   {


private Surface surface;
private Canvas canvas;
private SurfaceTexture mSurfaceTexture;
private boolean surfaceAvailable = false;


 public CanvasView(Context context) {
    super(context);
    init();
}

public CanvasView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
}

public CanvasView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init();
}

private void init(){
setOpaque(false);
setSurfaceTextureListener(this);

}


   public void draw(){
 canvas = surface.lockCanvas(null);
 canvas.drawColor(0, PorterDuff.Mode.CLEAR);
 //some drawing
 canvas.drawRect(qqqq, qq, sss, gggg, mPaint);
  //some drawing
 surface.unlockCanvasAndPost(canvas);
   }

 public CanvasView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
}

@Override
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
    this.surfaceAvailable = true;

    Toast.makeText(getContext(),"surface created ",Toast.LENGTH_LONG).show();



    mSurfaceTexture = surface;
    drawCanvas();



}

@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
    mSurfaceTexture = surface;



}

@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
    this.surfaceAvailable = false;
    Toast.makeText(getContext(),"surface Destroyed ",Toast.LENGTH_LONG).show();

    return false;
}

@Override
public void onSurfaceTextureUpdated(SurfaceTexture surface) {
    mSurfaceTexture = surface;

}


   public void drawCanvas()
    {
     if (this.surfaceAvailable) {
                       if(surface == null)
                        surface = new Surface(mSurfaceTexture);             
                        draw();
      }
   }


  }

第一次抽奖没有问题但当我从(android 7.0)上的应用程序退出并返回时，我看到TextureView的区域在调用Toast（表面创建）的同时它是黑色但是当我调用时绘制method called但是没有东西只绘制黑色TextureView

当片段恢复时，TextureView变黑

0 个答案: