設置查看可見性以隱形並獲取尺寸

Question

我有一個ImageView及其可見性設置爲GONE。我正試圖設置一個位圖資源並使其顯示。

我實現的ImageView的尺寸（我需要適當地進行二次採樣我的位圖）爲零時，它的能見度仍然GONE，所以我設置這行代碼我BitmapAsyncTask運行之前。

ImageView postImageView= (ImageView) getActivity().findViewById(R.id.post_image); 
// Set it as visible to take up necessary space for bitmap computation 
postImageView.setVisibility(View.INVISIBLE); 

尺寸還是回到零，並在進一步的測試中，ImageView的需要一些時間之前的知名度再次設置爲不可見。我現在修復的是AsyncTask內部的一個while循環，等待這些維度可用，但是我想知道是否有更好的方法來做到這一點？

我對當前的AsyncTask代碼：

@Override 
protected Bitmap doInBackground(Void... voids) { 
    Log.i(TAG,"BitmapWorkerTask initialized."); 
    while(mImageView.getWidth() ==0){ 
     // Wait for the ImageView to be ready 
     Log.i(TAG,"asd"); 
    } 
    int reqWidth = mImageView.getWidth()==0?1920:mImageView.getWidth(); 
    int reqHeight = mImageView.getHeight()==0?1080:mImageView.getHeight(); 
    Log.i(TAG, "Dimensions (required): "+reqWidth+" X "+ reqHeight); 
    //Decode and scale image 
    BitmapFactory.Options options = new BitmapFactory.Options(); 
    options.inJustDecodeBounds = true; 
    BitmapFactory.decodeFile(mCurrentPhotoPath, options); 
    Log.i(TAG, "Dimensions (source): "+options.outWidth+" X "+ options.outHeight); 

    options.inSampleSize = calculateInSampleSize(options,reqWidth, reqHeight); 
    options.inJustDecodeBounds = false; 
    Bitmap imageBitmap = BitmapFactory.decodeFile(mCurrentPhotoPath,options); 
    Log.i(TAG,"Dimensions (Bitmap): "+ imageBitmap.getWidth()+" X "+ imageBitmap.getHeight()); 

    return imageBitmap; 
} 

Answer 1

嘗試添加布局監聽，等待佈局來衡量：

final ImageView postImageView = (ImageView) getActivity().findViewById(R.id.post_image); 

postImageView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() { 
    @Override 
    public void onLayoutChange(View view, int i, int i2, int i3, int i4, int i5, int i6, int i7, int i8) { 
     postImageView.removeOnLayoutChangeListener(this); 
     Log.e(TAG, "W:" + postImageView.getWidth() + " H:"+postImageView.getHeight()); 
    } 
}); 

postImageView.setVisibility(View.INVISIBLE);