拖拽图像？

Question

我正在尝试做一些应用程序，这必须解锁时，用户移动图像到某个地方…但问题是，当用户触摸图像以外的其他地方时，它仍然会尝试移动，并给出这个错误: java.lang.ClassCastException: android.widget.AbsoluteLayout$LayoutParams

下面是我的代码：

公共类Main扩展了Activity {

private View selected_item;
private int offset_x = 0;
private int offset_y = 0;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    final ViewGroup vg = (ViewGroup) findViewById(R.id.lout);

    vg.setOnTouchListener(new View.OnTouchListener() {

        @SuppressWarnings("deprecation")
        public boolean onTouch(View v, MotionEvent event) {
                      switch (event.getAction()) {                          
                      case MotionEvent.ACTION_MOVE:
                          int x = (int) event.getX() - offset_x;
                          int y = (int) event.getY() - offset_y;
                          Log.e("SONUC", "SONUC1: " + x + ", " + y);
                          int w = getWindowManager().getDefaultDisplay().getWidth() - 25;
                          int h = getWindowManager().getDefaultDisplay().getHeight() - 25;
                          if (x > w)
                              x = w;
                          if (y > h)
                              y = h;
                          Log.e("SONUC", "SONUC2: " + x + ", " + y);
                          AbsoluteLayout.LayoutParams lp = new AbsoluteLayout.LayoutParams(
                                  new ViewGroup.MarginLayoutParams(
                                          AbsoluteLayout.LayoutParams.WRAP_CONTENT,
                                          AbsoluteLayout.LayoutParams.WRAP_CONTENT));                              
                          lp.x = x;
                          lp.y = y;
                          Log.e("SONUC", "SONUC3: " + lp);
                          selected_item.setLayoutParams(lp);       

                          break;

                      case MotionEvent.ACTION_UP:
                          offset_x = (int) event.getX() - offset_x;
                          offset_y = (int) event.getY() - offset_y;
                          Log.e("SONUC", "SONUC5: " + offset_x + ", " + offset_y);
                          selected_item = v;
                          if (offset_x < 220 && offset_x > 150 && offset_y < 330 && offset_y > 300)
                              startActivity(new Intent("com.yahya.GeneralTraining.UNLOCKED"));
                          break;

            default:
                break;
            }
            return true;
        }
    });

    ImageView img = (ImageView) findViewById(R.id.imageView1);
    img.setOnTouchListener(new View.OnTouchListener() {

        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {

            case MotionEvent.ACTION_DOWN:
                offset_x = (int) event.getX();
                offset_y = (int) event.getY();
                Log.e("SONUC", "SONUC4: " + offset_x + ", " + offset_y);                    
                selected_item = v;
                break;


            default:
                break;
            }
            return false;

        }
    });

}

}

Answer 1

您可以在viewgroup的onTouchListener中提供检查，以确认最初单击了该图像。

vg.setOnTouchListener(new View.OnTouchListener() {

    @SuppressWarnings("deprecation")
    public boolean onTouch(View v, MotionEvent event) {
                if(selected_item.getId() == R.id.image){
                    switch (event.getActionMasked()) {
                      //your code
                    }
                }
        }
        return true;
    }
});

Answer 2

第一件事不要创建LayoutParam的新对象，只需从容器中获取LayoutParam对象，如图像或布局

假设获取ImageView，然后

LayoutParam lp = imageView.getLayoutParam();

lp.width = newWidth;
lp.height = newHeight;

现在更改大小并在imageView.setLayoutParam()中设置它

imageView.setLayoutParam(lp);

另一件事是，您还为ViewGroup设置了触摸侦听器，仅为ImageView设置了触摸侦听器，而没有为ViewGroup设置触摸侦听器，并且在触摸侦听器实现中，返回true以指示触摸侦听器已实现