ImageView无法加载图像（jpg，png，...）

Question

我正尝试从我的res/drawable文件夹中加载图像。我使用了Android开发人员指南Link。 出于某种原因，它不工作。我得到的唯一错误是“SPAN_EXCLUSIVE_EXCLUSIVE跨度不能有零长度”，我研究它。显然它必须与自定义键盘有关，但我根本没有使用文本输入。应用程序本身没有崩溃。我希望你们能帮助我:) 布局文件只包含一个带有ImageView的RelativeLayout。

public class PixelActivity extends Activity { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_pixel); 
    String uri = "@drawable-hdpi/testbild.png"; 
    final int imageResource = getResources().getIdentifier(uri, null, getPackageName()); 


    final ImageView iv = (ImageView) findViewById(R.id.imageview1); 

    //int imageHeight = options.outHeight; 
    //int imageWidth = options.outWidth; 
    //String imageType = options.outMimeType; 
    new Thread(new Runnable() 
    { 

     public void run() 
     { 
      BitmapFactory.Options options = new BitmapFactory.Options(); 
      options.inJustDecodeBounds = true; 
      BitmapFactory.decodeResource(getResources(), imageResource, options); 


      iv.post(new Runnable() 
      { 

       public void run() 
       { 
        iv.setImageBitmap(decodeSampledBitmapFromResources(getResources(),imageResource,iv.getWidth(),iv.getHeight())); 
        //iv.setImageResource(R.drawable.testbild); 
       } 
      }); 
     } 
    }); 






} 

public static int calculateInSampleSize(BitmapFactory.Options options,int reqWidth, int reqHeight) 
{ 
    final int height = options.outHeight; 
    final int width = options.outWidth; 
    int inSampleSize = 1; 

    if(height > reqHeight || width > reqWidth) 
    { 
     final int heightRatio = Math.round((float)height/(float)reqHeight); 
     final int widthRatio = Math.round((float)width/(float)reqWidth); 

     inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio; 
    } 

    return inSampleSize; 
} 

public static Bitmap decodeSampledBitmapFromResources(Resources res, int resId, int reqWidth, int reqHeight) 
{ 
    final BitmapFactory.Options options = new BitmapFactory.Options(); 
    options.inJustDecodeBounds = true; 
    BitmapFactory.decodeResource(res, resId, options); 

    options.inSampleSize = calculateInSampleSize(options,reqWidth,reqHeight); 
    options.inJustDecodeBounds = false; 

    return BitmapFactory.decodeResource(res, resId, options); 
} 

}

Answer 1

String uri = "@drawable-hdpi/testbild.png"; 

这是无效的。删除-hdpi部分和.png部分，然后重试。或者，切换到提供所有三个参数getIdentifier()：

final int imageResource = getResources().getIdentifier("testbild", "drawable", getPackageName());