Question

所以我有一个imageview1，当它被点击一个新活动时，它会在下一个活动的新imageview2中显示相同的图像。点击的imageview1由我的mainactivity上的listview访问。列表视图由数组填充，每个列表视图项具有相应的图像。

因此，当单击listview项时，它将启动imageview1所在的新活动。使用xml typedarray填充此imageview，该类型引用可绘制图像。

我无法将图像从第一个图像视图传递到新活动的下一个图像视图。我收到了一个空指针异常，我在下面列出了这个异常。我是一个非常新的编程，我不确定如何解决这个问题。任何帮助都会非常感激。

继承我的routeDetails类，其中包含第一个imageview

public class RouteDetails extends AppCompatActivity {

ImageView routeImage;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_route_details);

    //TextView for route details
    final TextView routeDetailsView = (TextView) findViewById(R.id.routeDetailsView);
    routeDetailsView.setText(getIntent().getExtras().getString("route"));

    //ImageView for route details
    routeImage = (ImageView) findViewById(R.id.routeImage);
    routeImage.setImageResource(getIntent().getIntExtra("imageResourceId", 0));


    //passing image to fullscreenimage
    routeImage.setDrawingCacheEnabled(true);
    routeImage.buildDrawingCache();
    final Bitmap bitmap = routeImage.getDrawingCache();

////////// Trying to pass image to new activity

   routeImage.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view)
        {
            Intent i = new Intent(RouteDetails.this, FullScreenImage.class);
            //Bitmap _bitmap; // your bitmap
            ByteArrayOutputStream _bs = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.PNG, 50, _bs);
            i.putExtra("byteArray", _bs.toByteArray());
            startActivity(i);
        }

    });


////////////
}

并且我的全屏图像类试图将图像传递给

public class FullScreenImage extends AppCompatActivity {

TouchImageView routeImageFull;

@Override
protected void onCreate(Bundle saveInstanceState){
    super.onCreate(saveInstanceState);


    setContentView(R.layout.full_screen_image);
    routeImageFull = (TouchImageView) findViewById(R.id.fullScreenImageView);


    if(getIntent().hasExtra("byteArray")) {
        TouchImageView routeImageFull= new TouchImageView(this);
        Bitmap bitmap = BitmapFactory.decodeByteArray(
                getIntent().getByteArrayExtra("byteArray"),0,getIntent().getByteArrayExtra("byteArray").length);
        routeImageFull.setImageBitmap(bitmap);
    }
}
}

并且接下来的错误

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.example.zach.listview, PID: 3429
              java.lang.NullPointerException: Attempt to invoke virtual        method 'boolean     android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int,     java.io.OutputStream)' on a null object reference
                  at     com.example.zach.listview.RouteDetails$1.onClick(RouteDetails.java:47)
                  at android.view.View.performClick(View.java:5610)
                  at android.view.View$PerformClick.run(View.java:22265)
                  at android.os.Handler.handleCallback(Handler.java:751)
                  at android.os.Handler.dispatchMessage(Handler.java:95)
                  at android.os.Looper.loop(Looper.java:154)
                  at     android.app.ActivityThread.main(ActivityThread.java:6077)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

Answer 1

而不是传递整个位图。您只需将您在此处获取的资源ID发送到另一个活动，并且可以通过相同的方式显示图像，您在此处执行此操作。以下是更改后的代码。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_route_details);

    //TextView for route details
    final TextView routeDetailsView = (TextView)    
    findViewById(R.id.routeDetailsView);
    routeDetailsView.setText(getIntent().getExtras().getString("route"));

    //ImageView for route details
    routeImage = (ImageView) findViewById(R.id.routeImage);

    int mImageResource = getIntent().getIntExtra("imageResourceId", 0);
    routeImage.setImageResource(mImageResource);


   //passing image to fullscreenimage
   routeImage.setDrawingCacheEnabled(true);
   routeImage.buildDrawingCache();
   final Bitmap bitmap = routeImage.getDrawingCache();

   // Trying to pass image to new activity

   routeImage.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view)
        {
            Intent i = new Intent(RouteDetails.this,FullScreenImage.class);
            i.putExtra("mImageResource", mImageResource);
            startActivity(i);
        }

   });
}

将图像从imageview传递到第二个活动时出错

1 个答案: