Question

嘿我想将位图传递给另一个活动。为了避免“Failed binder transaction”异常，我压缩了位图。但是现在我得到了一个nullpointer异常，虽然我可以在imageview中显示图像，因此它包含数据。为了测试，我只传了一个字符串，工作正常。谢谢你的回答。

MainActivity.java

//Here I want to pass the bitmap
topBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);                
            camera.release();       
            bottomBitmap=MainActivity.scaleDownBitmap(bottomBitmap, 100,getApplicationContext());           
            Intent intent = new Intent(getApplicationContext(), DetailActivity.class);
            intent.putExtra("bottomBitmap", bottomBitmap);
            startActivity(intent);




//Method to compress bitmap
public static Bitmap scaleDownBitmap(Bitmap photo, int newHeight, Context context) {

     final float densityMultiplier = context.getResources().getDisplayMetrics().density;        

     int h= (int) (newHeight*densityMultiplier);
     int w= (int) (h * photo.getWidth()/((double) photo.getHeight()));

     photo=Bitmap.createScaledBitmap(photo, w, h, true);

     return photo;
     }

DetailActivity.java

private Bitmap bottomBitmap;
private ImageView bottomImage;



//Receive Data
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.detail_activity);       
    Intent intent = getIntent();
    this.bottomBitmap = (Bitmap) intent.getParcelableExtra("bottomBitmap");
    this.bottomImage.setImageBitmap(this.bottomBitmap);

}

日志：

04-28 21:56:13.317: E/AndroidRuntime(19456): FATAL EXCEPTION: main
04-28 21:56:13.317: E/AndroidRuntime(19456): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.campic/com.example.campic.DetailActivity}: java.lang.NullPointerException
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2517)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2574)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.ActivityThread.access$600(ActivityThread.java:162)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1413)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.os.Handler.dispatchMessage(Handler.java:99)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.os.Looper.loop(Looper.java:158)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.ActivityThread.main(ActivityThread.java:5789)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at java.lang.reflect.Method.invokeNative(Native Method)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at java.lang.reflect.Method.invoke(Method.java:525)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:843)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at dalvik.system.NativeStart.main(Native Method)
04-28 21:56:13.317: E/AndroidRuntime(19456): Caused by: java.lang.NullPointerException
04-28 21:56:13.317: E/AndroidRuntime(19456):    at com.example.campic.DetailActivity.onCreate(DetailActivity.java:22)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.Activity.performCreate(Activity.java:5195)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1111)
04-28 21:56:13.317: E/AndroidRuntime(19456):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2473)
04-28 21:56:13.317: E/AndroidRuntime(19456):    ... 11 more

Answer 1

在DetailActivity：

private ImageView bottomImage;
...
this.bottomImage.setImageBitmap(this.bottomBitmap);

bottomImage永远不会被初始化。您可能需要先使用findViewById初始化变量，然后再调用setImageBitmap。

Android：将压缩位图传递给Activity（NullPointerException）

1 个答案: