public class MainActivity extends AppCompatActivity implements View.OnTouchListener {
private ViewGroup gestureListenerGroup;
private GestureDetector gestureDetector;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
gestureListenerGroup = findViewById(R.id.gesture_listen_layout);
gestureListenerGroup.setOnTouchListener(this);
gestureDetector = new GestureDetector(this, new SimpleOnGestureListener());
}
@Override
public boolean onTouch(View v, MotionEvent event) {
// 单指双击 https://www.jianshu.com/p/95b3fdc46b0f
gestureDetector.onTouchEvent(event);
// 双指缩放 https://www.jianshu.com/p/b27e04b787c3
isMultiPointerZoom(event);
// 双指双击 https://stackoverflow.com/questions/12414680/how-to-implement-a-two-finger-double-click-in-android
is2FingerDoubleClick(event);
return true;
}
private static final int TIMEOUT = ViewConfiguration.getDoubleTapTimeout() + 100;
private long mFirstDownTime = 0;
private boolean mSeparateTouches = false;
private byte mTwoFingerTapCount = 0;
private void is2FingerDoubleClick(MotionEvent event) {
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
if (mFirstDownTime == 0 || event.getEventTime() - mFirstDownTime > TIMEOUT)
reset(event.getDownTime());
break;
case MotionEvent.ACTION_POINTER_UP:
if (event.getPointerCount() == 2)
mTwoFingerTapCount++;
else
mFirstDownTime = 0;
break;
case MotionEvent.ACTION_UP:
if (!mSeparateTouches)
mSeparateTouches = true;
else if (mTwoFingerTapCount == 2 && event.getEventTime() - mFirstDownTime < TIMEOUT) {
mFirstDownTime = 0;
Toast.makeText(MainActivity.this, "双指双击事件", Toast.LENGTH_SHORT).show();
}
}
}
private void reset(long time) {
mFirstDownTime = time;
mSeparateTouches = false;
mTwoFingerTapCount = 0;
}
private float mFirstTouchX;
private float mFirstTouchY;
private float mSecondTouchX;
private float mSecondTouchY;
private double firstPointerLength;
private double secondPointerLength;
// 双指缩放 双指先拖动再进行缩放操作 会认为仍然是双指缩放操作
private void isMultiPointerZoom(MotionEvent event) {
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
//获取第一个点（A点）的位置
mFirstTouchX = event.getX();
mFirstTouchY = event.getY();
break;
case MotionEvent.ACTION_POINTER_DOWN:
if (event.getActionIndex() == 1) {
//获取第二个点（B点）的位置
mSecondTouchX = event.getX(1);
mSecondTouchY = event.getY(1);
//根据两点的位置获取两个触摸点之间的距离（AB）
float firstLengthX = Math.abs(mFirstTouchX - mSecondTouchX);
float firstLengthY = Math.abs(mFirstTouchY - mSecondTouchY);
firstPointerLength = Math.sqrt(Math.pow(firstLengthX, 2) + Math.pow(firstLengthY, 2));
}
break;
case MotionEvent.ACTION_MOVE:
if (event.getPointerCount() >= 2) {
//获取第一个点（A‘）的位置
float firstX = event.getX(0);
float firstY = event.getY(0);
//获取第二个点（B‘）的位置
float secondX = event.getX(1);
float secondY = event.getY(1);
//计算两点之间的距离（A'B'）
float secondLengthX = Math.abs(firstX - secondX);
float secondLengthY = Math.abs(firstY - secondY);
secondPointerLength = Math.sqrt(Math.pow(secondLengthX, 2) + Math.pow(secondLengthY, 2));
}
break;
case MotionEvent.ACTION_UP:
//最后一根手指离开时触发
double zoomDistance = Math.abs(secondPointerLength - firstPointerLength);
if (zoomDistance > 10) {
Toast.makeText(MainActivity.this, "缩放距离" + zoomDistance, Toast.LENGTH_SHORT).show();
}
mFirstTouchX = 0;
mFirstTouchY = 0;
mSecondTouchX = 0;
mSecondTouchY = 0;
firstPointerLength = 0;
secondPointerLength = 0;
break;
}
}
// 单指双击 如果用户手指第二次点击后长时间没有离开屏幕 也会认为是双击事件
class SimpleOnGestureListener extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onDoubleTap(MotionEvent e) {
Toast.makeText(MainActivity.this, "单指双击屏幕", Toast.LENGTH_SHORT).show();
return super.onDoubleTap(e);
}
}
}