[英]How to avoid Android button dragging out side the screen
我已經在我的應用程序中實現了按鈕拖動,但它解決了問題是為什么我拖動按鈕走出側面我無法看到按鈕。 但要解決它。 我需要拖動屏幕。 我試過下面的代碼,如果有任何錯誤糾正我,
@Override
public boolean onTouch(View v, MotionEvent event)
{
final int d_X = (int) event.getRawX();
final int d_Y = (int) event.getRawY();
PointF start = new PointF();
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
start.set(event.getX(),event.getY());
if(shouldAllowToDrag) // if it true then i will allow to drag.
{
RelativeLayout.LayoutParams lParams = (RelativeLayout.LayoutParams) v.getLayoutParams();
_xDelta = d_X - lParams.leftMargin;
_yDelta = d_Y - lParams.topMargin;
}
else
{
//check for double click
long pressTime = System.currentTimeMillis();
// If double click...
String buttonTitle = moveButton.getText().toString();
if (pressTime - lastPressTime <= DOUBLE_PRESS_INTERVAL) {
Log.i(TAG,"doubleTappedistrue");
hasLatchedDown = false;
if(buttonTitle.equals("Unlocked"))
{
hasButtonUnlocked = false;
moveButton.setText("Locked");
}
else if(buttonTitle.equals("Locked"))
{
hasButtonUnlocked = true;
moveButton.setText("Unlocked");
}
}
else
{
hasLatchedDown = true;
buttonLastStateText = buttonTitle;
moveButton.setText("Unlocked");
}
lastPressTime = pressTime;
}
break;
case MotionEvent.ACTION_UP:
if(!shouldAllowToDrag)
{
if(hasLatchedDown)
{
hasLatchedDown = false;
moveButton.setText(buttonLastStateText);
}
}
break;
case MotionEvent.ACTION_POINTER_DOWN:
break;
case MotionEvent.ACTION_POINTER_UP:
break;
case MotionEvent.ACTION_MOVE:
if(shouldAllowToDrag){
View parentView = (View) v.getParent();
parentView.getWidth();
parentView.getHeight();
imageView.getWidth();
RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) v.getLayoutParams();
layoutParams.leftMargin = d_X - _xDelta;
layoutParams.topMargin = d_Y - _yDelta;
v.setLayoutParams(layoutParams);
}
break;
}
return true;
}
您應該添加最小/最大檢查:
layoutParams.leftMargin = Math.min(Math.max(d_X - _xDelta,0), parentView.getWidth() - layoutParams.width);
topMargin也是一樣的想法。 (代碼未編譯檢查)讓我知道這是否有幫助。
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