我正在尝试在 android studio 中创建一个简单的拖放图像。我可以让图像在屏幕上拖动,一旦我释放它就会消失。在控制台中,我得到一个“报告丢弃结果:假”
这是我的代码:
ImageView mImageView;
String mString;
private android.widget.RelativeLayout.LayoutParams mLayoutParams;
mImageView.setOnLongClickListener(new View.OnLongClickListener(){
@Override
public boolean onLongClick(View v){
ClipData.Item item = new ClipData.Item((CharSequence)v.getTag());
String[] mimeTypes = {
ClipDescription.MIMETYPE_TEXT_PLAIN
};
ClipData dragData = new ClipData(v.getTag().toString(), mimeTypes, item);
View.DragShadowBuilder myShadow = new View.DragShadowBuilder(mImageView);
v.startDrag(dragData, myShadow, null, 0);
return true;
}
});
mImageView.setOnDragListener(new View.OnDragListener() {
@Override
public boolean onDrag(View v, DragEvent event) {
switch(event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED:
mLayoutParams = (RelativeLayout.LayoutParams)v.getLayoutParams();
Log.d(mString, "Action is DragEvent.ACTION_DRAG_STARTED");
// Do nothing
break;
case DragEvent.ACTION_DRAG_ENTERED:
Log.d(mString, "Action is DragEvent.ACTION_DRAG_ENTERED");
int x_cord = (int) event.getX();
int y_cord = (int) event.getY();
break;
case DragEvent.ACTION_DRAG_EXITED :
Log.d(mString, "Action is DragEvent.ACTION_DRAG_EXITED");
x_cord = (int) event.getX();
y_cord = (int) event.getY();
mLayoutParams.leftMargin = x_cord;
mLayoutParams.topMargin = y_cord;
v.setLayoutParams(mLayoutParams);
break;
case DragEvent.ACTION_DRAG_LOCATION :
Log.d(mString, "Action is DragEvent.ACTION_DRAG_LOCATION");
x_cord = (int) event.getX();
y_cord = (int) event.getY();
break;
case DragEvent.ACTION_DRAG_ENDED :
Log.d(mString, "Action is DragEvent.ACTION_DRAG_ENDED");
// Do nothing
break;
case DragEvent.ACTION_DROP:
Log.d(mString, "ACTION_DROP event");
// Do nothing
break;
default: break;
}
return true;
}
});
mImageView.setOnTouchListener(new View.OnTouchListener(){
@Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
ClipData data = ClipData.newPlainText("", "");
View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(mImageView);
mImageView.startDrag(data, shadowBuilder, mImageView, 0);
mImageView.setVisibility(View.INVISIBLE);
return true;
} else {
return false;
}
}
});
}
}
最佳答案
已编辑:更改为如何使用 onTouch 移动 RelativeLayout 中包含的所有 View 的工作示例。我认为 onDrag 事件更适用于拖放数据项,而不是移动 View 。
public class MainActivity extends AppCompatActivity implements View.OnTouchListener {
private RelativeLayout mRelLay;
private float mInitialX, mInitialY;
private int mInitialLeft, mInitialTop;
private View mMovingView = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRelLay = (RelativeLayout) findViewById(R.id.relativeLayout);
for (int i = 0; i < mRelLay.getChildCount(); i++)
mRelLay.getChildAt(i).setOnTouchListener(this);
}
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
RelativeLayout.LayoutParams mLayoutParams;
switch (motionEvent.getAction()) {
case MotionEvent.ACTION_DOWN:
mMovingView = view;
mLayoutParams = (RelativeLayout.LayoutParams) mMovingView.getLayoutParams();
mInitialX = motionEvent.getRawX();
mInitialY = motionEvent.getRawY();
mInitialLeft = mLayoutParams.leftMargin;
mInitialTop = mLayoutParams.topMargin;
break;
case MotionEvent.ACTION_MOVE:
if (mMovingView != null) {
mLayoutParams = (RelativeLayout.LayoutParams) mMovingView.getLayoutParams();
mLayoutParams.leftMargin = (int) (mInitialLeft + motionEvent.getRawX() - mInitialX);
mLayoutParams.topMargin = (int) (mInitialTop + motionEvent.getRawY() - mInitialY);
mMovingView.setLayoutParams(mLayoutParams);
}
break;
case MotionEvent.ACTION_UP:
mMovingView = null;
break;
}
return true;
}
}
关于android - 无法在android studio中拖放一个简单的imageView,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41183214/