创建一个自定义的触摸监听器类(在Kotlin中):

(这段代码限制了视图从父视图中拖出)

class CustomTouchListener(
  val screenWidth: Int, 
  val screenHeight: Int
) : View.OnTouchListener {
    private var dX: Float = 0f
    private var dY: Float = 0f

    override fun onTouch(view: View, event: MotionEvent): Boolean {

        val newX: Float
        val newY: Float

        when (event.action) {
            MotionEvent.ACTION_DOWN -> {
                dX = view.x - event.rawX
                dY = view.y - event.rawY
            }
            MotionEvent.ACTION_MOVE -> {

                newX = event.rawX + dX
                newY = event.rawY + dY

                if ((newX <= 0 || newX >= screenWidth - view.width) || (newY <= 0 || newY >= screenHeight - view.height)) {
                    return true
                }

                view.animate()
                    .x(newX)
                    .y(newY)
                    .setDuration(0)
                    .start()
            }
        }
        return true
    }
}

如何使用它?

parentView.viewTreeObserver.addOnGlobalLayoutListener { view.setOnTouchListener(CustomTouchListener(parentView.width, parentView.height)) }

parentView是视图的父视图。

我推荐使用view。translationX和view。翻译来移动你的观点。

Kotlin snippet:

yourView.translationX = xTouchCoordinate
yourView.translationY = yTouchCoordinate

就像这样:

public class MyActivity extends Activity implements View.OnTouchListener {

TextView _view;
ViewGroup _root;
private int _xDelta;
private int _yDelta;

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

    _root = (ViewGroup)findViewById(R.id.root);

    _view = new TextView(this);
    _view.setText("TextView!!!!!!!!");

    RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(150, 50);
    layoutParams.leftMargin = 50;
    layoutParams.topMargin = 50;
    layoutParams.bottomMargin = -250;
    layoutParams.rightMargin = -250;
    _view.setLayoutParams(layoutParams);

    _view.setOnTouchListener(this);
    _root.addView(_view);
}

public boolean onTouch(View view, MotionEvent event) {
    final int X = (int) event.getRawX();
    final int Y = (int) event.getRawY();
    switch (event.getAction() & MotionEvent.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN:
            RelativeLayout.LayoutParams lParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
            _xDelta = X - lParams.leftMargin;
            _yDelta = Y - lParams.topMargin;
            break;
        case MotionEvent.ACTION_UP:
            break;
        case MotionEvent.ACTION_POINTER_DOWN:
            break;
        case MotionEvent.ACTION_POINTER_UP:
            break;
        case MotionEvent.ACTION_MOVE:
            RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
            layoutParams.leftMargin = X - _xDelta;
            layoutParams.topMargin = Y - _yDelta;
            layoutParams.rightMargin = -250;
            layoutParams.bottomMargin = -250;
            view.setLayoutParams(layoutParams);
            break;
    }
    _root.invalidate();
    return true;
}}

在main.xml中只需要RelativeLayout + @+id/root即可

创建一个自定义的触摸监听器类(在Kotlin中):

(这段代码限制了视图从父视图中拖出)

class CustomTouchListener(
  val screenWidth: Int, 
  val screenHeight: Int
) : View.OnTouchListener {
    private var dX: Float = 0f
    private var dY: Float = 0f

    override fun onTouch(view: View, event: MotionEvent): Boolean {

        val newX: Float
        val newY: Float

        when (event.action) {
            MotionEvent.ACTION_DOWN -> {
                dX = view.x - event.rawX
                dY = view.y - event.rawY
            }
            MotionEvent.ACTION_MOVE -> {

                newX = event.rawX + dX
                newY = event.rawY + dY

                if ((newX <= 0 || newX >= screenWidth - view.width) || (newY <= 0 || newY >= screenHeight - view.height)) {
                    return true
                }

                view.animate()
                    .x(newX)
                    .y(newY)
                    .setDuration(0)
                    .start()
            }
        }
        return true
    }
}

如何使用它?

parentView.viewTreeObserver.addOnGlobalLayoutListener { view.setOnTouchListener(CustomTouchListener(parentView.width, parentView.height)) }

parentView是视图的父视图。

我发现了一个简单的方法来做到这一点与ViewPropertyAnimator:

float dX, dY;

@Override
public boolean onTouch(View view, MotionEvent event) {

    switch (event.getAction()) {

        case MotionEvent.ACTION_DOWN:

            dX = view.getX() - event.getRawX();
            dY = view.getY() - event.getRawY();
            break;

        case MotionEvent.ACTION_MOVE:

            view.animate()
                    .x(event.getRawX() + dX)
                    .y(event.getRawY() + dY)
                    .setDuration(0)
                    .start();
            break;
        default:
            return false;
    }
    return true;
}

按照@Andrew方法，如果你想要移动视图的中心，你只需要减去视图的一半高度和一半宽度。

float dX, dY;

@Override
public boolean onTouchEvent(View view, MotionEvent event) {
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            dX = view.getX() - event.getRawX();
            dY = view.getY() - event.getRawY();
            break;
        case MotionEvent.ACTION_MOVE:
            view.animate()
                .x(event.getRawX() + dX - (view.getWidth() / 2f))
                .y(event.getRawY() + dY - (view.getHeight() / 2f))
                .setDuration(0)
                .start();
            break;
        default:
            return false;
    }
    return true;
}