Android：無法將矩陣imageview放置在屏幕中央？

Question

我正在研究圖像縮放。一切都很好。我試圖在佈局的中心顯示矩陣圖像。但我無法做到。

我的XML是：

<FrameLayout 
    android:id="@+id/root1" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:layout_below="@+id/root" 
    > 

    <ImageView 
     android:id="@+id/img" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:layout_gravity="center" 
     android:adjustViewBounds="true" 
     android:scaleType="matrix" 
     android:src="@drawable/ic_launcher" > 
    </ImageView> 
</FrameLayout> 

而且我用從堆棧溢出，這個解決方案，但我沒有得到中心放置的圖像。圖像對齊屏幕的左上角。請幫幫我。

@Override 
public void onWindowFocusChanged(boolean hasFocus) { 

    super.onWindowFocusChanged(hasFocus); 

    screenWidth = rel.getWidth(); 
    screenHeight = rel.getHeight(); 

    Log.e("", 
      "Image Width : " + image.getWidth() + " > " 
        + image.getHeight()); 
    Log.e("", "screen Width : " + screenWidth + " > " + screenHeight); 
    Matrix matrix = image.getImageMatrix(); 
    RectF drawableRect = new RectF(0, 0, image.getWidth(), 
      image.getHeight()); 
    RectF viewRect = new RectF(0, 0, screenWidth, screenHeight); 
    matrix.setRectToRect(drawableRect, viewRect, Matrix.ScaleToFit.CENTER); 
    image.setImageMatrix(matrix); 
    image.invalidate(); 
} 

Answer 1

在這裏，我用繪製（被設置爲ImageView的）內部寬度和高度屏幕寬度和screenHeight

這裏是我的解決方案：

@Override 
public void onWindowFocusChanged(boolean hasFocus) { 

    super.onWindowFocusChanged(hasFocus); 

    float imageWidth = imageView.getDrawable().getIntrinsicWidth(); 
    float imageHeight = imageView.getDrawable().getIntrinsicHeight(); 
    RectF drawableRect = new RectF(0, 0, imageWidth, imageHeight); 
    RectF viewRect = new RectF(0, 0, imageView.getWidth(), 
      imageView.getHeight()); 
    Matrix matrix = imageView.getMatrix(); 
    matrix.setRectToRect(drawableRect, viewRect, Matrix.ScaleToFit.CENTER); 
    imageView.setImageMatrix(matrix); 
    imageView.invalidate(); 

}