Android开发笔记（四十五）手势事件

	private ScrollTextView tv_rough;
	private GestureDetector mGesture;
	
		tv_rough = (ScrollTextView) findViewById(R.id.tv_rough);
		tv_rough.setOnTouchListener(this);
		mGesture = new GestureDetector(this, this);
		
	@Override
	public boolean onTouch(View v, MotionEvent event) {
		return mGesture.onTouchEvent(event);
	}

@Override
public boolean onTouch(View v, MotionEvent event) {
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
    case MotionEvent.ACTION_MOVE:
        getParent().requestDisallowInterceptTouchEvent(true);
        ...//响应手势
        break;
    case MotionEvent.ACTION_UP:
    case MotionEvent.ACTION_CANCEL:
        ...//处理完毕
        getParent().requestDisallowInterceptTouchEvent(false);
        break;
    }
}

import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ScrollView;


@SuppressLint("ClickableViewAccessibility")
public class CustomScrollView extends ScrollView {
	private final static String TAG = "CustomScrollView";
	private float mOffsetX;
	private float mOffsetY;
	private float mLastPosX;
	private float mLastPosY;


	public CustomScrollView(Context context) {
		super(context);
	}


	public CustomScrollView(Context context, AttributeSet attr) {
		super(context, attr);
		setFadingEdgeLength(0);
	}


	@Override
	public boolean dispatchTouchEvent(MotionEvent event) {
		return super.dispatchTouchEvent(event);
	}


	@Override
	public boolean onTouchEvent(MotionEvent event) {
		return super.onTouchEvent(event);
	}


	@Override
	public boolean onInterceptTouchEvent(MotionEvent event) {
		Log.d(TAG, "onInterceptTouchEvent");
		boolean result = false;
		switch (event.getAction()) {
		case MotionEvent.ACTION_DOWN:
			mOffsetX = 0.0F;
			mOffsetY = 0.0F;
			mLastPosX = event.getX();
			mLastPosY = event.getY();
			result = super.onInterceptTouchEvent(event); // false传给子控件
			break;
		default:
			float thisPosX = event.getX();
			float thisPosY = event.getY();
			mOffsetX += Math.abs(thisPosX - mLastPosX); // x轴偏差
			mOffsetY += Math.abs(thisPosY - mLastPosY); // y轴偏差
			mLastPosX = thisPosX;
			mLastPosY = thisPosY;
			if (mOffsetX < 3 && mOffsetY < 3) {
				result = false; // false传给子控件（点击事件）
			} else if (mOffsetX < mOffsetY) {
				result = true; // true不传给子控件（垂直滑动）
			} else {
				result = false; // false传给子控件
			}
			break;
		}
		return result;
	}
}

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">ScrollTextView控件的源码如下：</span>

import android.content.Context;
import android.util.AttributeSet;
import android.widget.Scroller;
import android.widget.TextView;

public class ScrollTextView extends TextView {

    private static final String TAG = "ScrollTextView";
    private Scroller mScroller;
  
    public ScrollTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mScroller = new Scroller(context);
    }
  
    public void smoothScrollTo(int fx, int fy) {
        int dx = fx - mScroller.getFinalX();
        int dy = fy - mScroller.getFinalY();
        smoothScrollBy(dx, dy);
    }
  
    public void smoothScrollBy(int dx, int dy) {
        //设置滚动偏移量，注意正数是往左滚往上滚，负数才是往右滚往下滚
        mScroller.startScroll(mScroller.getFinalX(), mScroller.getFinalY(), -dx, -dy);
        //调用invalidate()才能保证computeScroll()会被调用
        invalidate();
    }
       
    @Override
    public void computeScroll() {
        //先判断mScroller滚动是否完成
        if (mScroller.computeScrollOffset()) {
            //这里调用View的scrollTo()完成实际的滚动
            scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
            //刷新页面
            postInvalidate();
        }
        super.computeScroll();
    }
}

import com.example.exmgesture.widget.ScrollTextView;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;

@SuppressLint("ClickableViewAccessibility")
public class RoughActivity extends Activity implements OnTouchListener,OnGestureListener {

	private final static String TAG = "RoughActivity";
	private ScrollTextView tv_rough;
	private GestureDetector mGesture;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_rough);
		
		tv_rough = (ScrollTextView) findViewById(R.id.tv_rough);
		tv_rough.setOnTouchListener(this);
		mGesture = new GestureDetector(this, this);
	}
	
	@Override
	public boolean dispatchTouchEvent(MotionEvent ev) {
		// TODO Auto-generated method stub
		return super.dispatchTouchEvent(ev);
	}
	
	@Override
	public boolean onTouch(View v, MotionEvent event) {
		return mGesture.onTouchEvent(event);
	}

	@Override
	public boolean onDown(MotionEvent e) {
		return true;
	}

	@Override
	public void onShowPress(MotionEvent e) {
	}

	@Override
	public boolean onSingleTapUp(MotionEvent e) {
		tv_rough.setText("您轻轻点击了一下");
		return false;
	}

	@Override
	public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
		return true;
	}

	@Override
	public void onLongPress(MotionEvent e) {
	}

	@Override
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
		tv_rough.setText("您拖动我啦");
		float offsetX = e2.getRawX() - e1.getRawX();
		float offsetY = e2.getRawY() - e1.getRawY();
		tv_rough.smoothScrollBy((int)offsetX, (int)offsetY);
		return false;
	}

}