從android的getDrawingCache（）獲取空位圖

Question

這是我的代碼。我得到空值。我試圖找出解決方案，因爲早晨，我已經創建了使用xml文件的佈局，然後我得到了位圖的視圖，但我想它動態和I have created layout programatically見下面的代碼。 我的看法是出現罰款，但仍getting getDrawingCache() null bitmap

LinearLayout mainlayout = new LinearLayout(getApplicationContext()); 
     mainlayout.setOrientation(LinearLayout.VERTICAL); 
     mainlayout.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); 
     ImageView top= new ImageView(getApplicationContext()); 
     ImageView bot= new ImageView(getApplicationContext()); 
      Bitmap bottomImage = BitmapFactory.decodeResource(getResources(), R.drawable.collagebot); 
      Bitmap topImage =BitmapFactory.decodeResource(getResources(), R.drawable.collagetop); 
      top.setImageBitmap(topImage); 
      bot.setImageBitmap(bottomImage); 

      LinearLayout midLayout = new LinearLayout(getApplicationContext()); 
         midLayout.setOrientation(LinearLayout.HORIZONTAL); 
         midLayout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT)); 
           Bitmap midlaybg =BitmapFactory.decodeResource(getResources(), R.drawable.bg); 
           Drawable middrow = new BitmapDrawable(getResources(),midlaybg); 
         midLayout.setBackground(middrow); 

        ImageView right= new ImageView(getApplicationContext()); 
        ImageView left= new ImageView(getApplicationContext()); 
        Bitmap rightImage = BitmapFactory.decodeResource(getResources(), R.drawable.fb); 
        Bitmap leftImage =BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher); 
        Drawable rightdrow = new BitmapDrawable(getResources(),rightImage); 
        Drawable leftdrow = new BitmapDrawable(getResources(),leftImage); 
        right.setBackground(rightdrow); 
        left.setBackground(leftdrow); 
        right.setLayoutParams(new LayoutParams(150,150)); 

        left.setLayoutParams(new LayoutParams(150,150)); 
        left.setLayoutParams(new LinearLayout.LayoutParams(150, 150, 10)); 
        midLayout.setPadding(50, 0, 0, 0); 
        midLayout.addView(right); 
        midLayout.addView(left); 

        mainlayout.addView(top); 
        mainlayout.addView(midLayout); 
        mainlayout.addView(bot); 

        Bitmap mainlaybg =BitmapFactory.decodeResource(getResources(), R.drawable.bg); 
        Drawable maindrow = new BitmapDrawable(getResources(),mainlaybg); 
        mainlayout.setBackground(maindrow); 

        mainlayout.setDrawingCacheEnabled(true); 
         mainlayout.buildDrawingCache(); 

       // setContentView(mainlayout); // i dont want to setContentView 


        Log.e("ceche",""+mainlayout.getDrawingCache());// here i am getting null bitmap of mainlayout view 
        Bitmap imgb=mainlayout.getDrawingCache(); 

Answer 1

mainlayout.measure(MeasureSpec.makeMeasureSpec(
      mainlayout.getLayoutParams().width, MeasureSpec.EXACTLY), 
      MeasureSpec.makeMeasureSpec(
        mainlayout.getLayoutParams().height, 
        MeasureSpec.EXACTLY)); 
    mainlayout.layout(0, 0, mainlayout.getMeasuredWidth(), 
      mainlayout.getMeasuredHeight()); 

    mainlayout.setDrawingCacheEnabled(true); 
    final Bitmap bitmap_ = Bitmap 
      .createBitmap(mainlayout.getDrawingCache()); 
    mainlayout.setDrawingCacheEnabled(true);