TextViews重力不垂直工作

Question

當我將TextView的DrawingCache繪製到另一個View的Canvas時，TextView的重力在垂直方向上沒有效果。

這裏的類繪製TextViews帆布把自己的畫布：

public class GravityDecorator extends View{ 
    private View view; 
    private Paint paint= new Paint(); 

    public GravityDecorator(View view,Context context) { 
     super(context); 
     this.view = view; 
     view.setDrawingCacheEnabled(true); 
     view.layout(0, 0,600,500); 
     this.layout(0, 0,600,500); 
     invalidate(); 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     super.onDraw(canvas); 
     view.buildDrawingCache();  
     canvas.drawBitmap(view.getDrawingCache(), 0, 0, paint);  
     view.destroyDrawingCache(); 
    } 

} 

下面是測試它的代碼（的onCreate）：

ViewGroup root = (ViewGroup) findViewById(R.id.root); // is a linear_layout - width and height is match_parent 
    TextView tv = new TextView(getApplicationContext()); 
    tv.setText("Hello World!"); 
    tv.setTextSize(40.0f);  
    tv.setLayoutParams(new LinearLayout.LayoutParams(300,200));  
    tv.setTextColor(Color.WHITE); 
    tv.setBackgroundColor(Color.parseColor("#3131c5")); 
    tv.setGravity(Gravity.CENTER); 

    GravityDecorator gd = new GravityDecorator(tv, getApplicationContext()); 
    root.addView(gd); 

正如你看到的，TextViews內容的嚴重性只在水平方向生效。

什麼原因和如何解決這個問題，如果它的錯誤？

謝謝

Answer 1

root = (ViewGroup) findViewById(R.id.root); // is a linear_layout - width and height is match_parent 
tv = new TextView(getApplicationContext()); 
tv.setText("Hello World!"); 
tv.setTextSize(40.0f);  
tv.setLayoutParams(new LinearLayout.LayoutParams(300,200));  
tv.setTextColor(Color.WHITE); 
tv.setBackgroundColor(Color.parseColor("#3131c5")); 
tv.setGravity(Gravity.CENTER); 
tv.invalidate(); 
root.addView(tv); 
GravityDecorator gd = new GravityDecorator(tv, getApplicationContext()); 
root.addView(gd); 

可能是因爲佈局參數是沒有得到的TextView初始設定。嘗試將視圖添加到Parent，然後獲取drawingCache。

public class GravityDecorator extends View{ 
    private View view; 
    private Paint paint= new Paint(); 

    public GravityDecorator(View view,Context context) { 
     super(context); 
     this.view = view; 
     view.setDrawingCacheEnabled(true); 
     view.layout(0, 0,600,500); 
     this.layout(0, 0,600,500); 
     invalidate(); 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     super.onDraw(canvas); 
     view.buildDrawingCache();  

     Bitmap bmp = view.getDrawingCache(); 

     canvas.drawBitmap(bmp, 0, 0, paint);  
     view.destroyDrawingCache(); 
     if(root.indexOfChild(tv) != -1) 
      root.removeView(tv); 


    } 

}