Android自定义长按事件

比如当希望长按的时间更长一点的时候。这时候就需要自己来定义这个长按事件了。下面是去年我写代码的时候，自定义长按事件的方式：

package chroya.fun;

import android.content.Context;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;

public class LongPressView1 extends View{
	private int mLastMotionX, mLastMotionY;
	//是否移动了
	private boolean isMoved;
	//是否释放了
	private boolean isReleased;
	//计数器，防止多次点击导致最后一次形成longpress的时间变短
	private int mCounter;
	//长按的runnable
	private Runnable mLongPressRunnable;
	//移动的阈值
	private static final int TOUCH_SLOP = 20;

	public LongPressView1(Context context) {
		super(context);
		mLongPressRunnable = new Runnable() {
			
			@Override
			public void run() {
				mCounter--;
				//计数器大于0，说明当前执行的Runnable不是最后一次down产生的。
				if(mCounter>0 || isReleased || isMoved) return;
				performLongClick();
			}
		};
	}

	public boolean dispatchTouchEvent(MotionEvent event) {
		int x = (int) event.getX();
		int y = (int) event.getY();
		
		switch(event.getAction()) {
		case MotionEvent.ACTION_DOWN:
			mLastMotionX = x;
			mLastMotionY = y;
			mCounter++;
			isReleased = false;
			isMoved = false;
			postDelayed(mLongPressRunnable, ViewConfiguration.getLongPressTimeout());
			break;
		case MotionEvent.ACTION_MOVE:
			if(isMoved) break;
			if(Math.abs(mLastMotionX-x) > TOUCH_SLOP 
					|| Math.abs(mLastMotionY-y) > TOUCH_SLOP) {
				//移动超过阈值，则表示移动了
				isMoved = true;
			}
			break;
		case MotionEvent.ACTION_UP:
			//释放了
			isReleased = true;
			break;
		}
		return true;
	}
}

代码里注释的比较清楚。主要思路是在down的时候，让一个Runnable一段时间后执行，如果时间到了，没有移动超过定义的阈值，也没有释放，则触发长按事件。在真实环境中，当长按触发之后，还需要将后来的move和up事件屏蔽掉。此处是示例，就略去了。

package chroya.fun;

import android.content.Context;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;

public class LongPressView2 extends View{
	private int mLastMotionX, mLastMotionY;
	//是否移动了
	private boolean isMoved;
	//长按的runnable
	private Runnable mLongPressRunnable;
	//移动的阈值
	private static final int TOUCH_SLOP = 20;

	public LongPressView2(Context context) {
		super(context);
		mLongPressRunnable = new Runnable() {
			
			@Override
			public void run() {				
				performLongClick();
			}
		};
	}

	public boolean dispatchTouchEvent(MotionEvent event) {
		int x = (int) event.getX();
		int y = (int) event.getY();
		
		switch(event.getAction()) {
		case MotionEvent.ACTION_DOWN:
			mLastMotionX = x;
			mLastMotionY = y;
			isMoved = false;
			postDelayed(mLongPressRunnable, ViewConfiguration.getLongPressTimeout());
			break;
		case MotionEvent.ACTION_MOVE:
			if(isMoved) break;
			if(Math.abs(mLastMotionX-x) > TOUCH_SLOP 
					|| Math.abs(mLastMotionY-y) > TOUCH_SLOP) {
				//移动超过阈值，则表示移动了
				isMoved = true;
				removeCallbacks(mLongPressRunnable);
			}
			break;
		case MotionEvent.ACTION_UP:
			//释放了
			removeCallbacks(mLongPressRunnable);
			break;
		}
		return true;
	}
}

思路跟第一种差不多，不过，在移动超过阈值和释放之后，会将Runnable从事件队列中remove掉，长按事件也就不会再触发了。源码中实现长按的原理也基本如此。

工程见附件。

• Funny.zip (53.6 KB)
• 下载次数: 646

  http://chroya.iteye.com/blog/804706

   

   Activity调用。
  

  public class MainActivity extends Activity {
  	
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          
          View mLongPressView = new LongPressView(this);
          mLongPressView.setOnLongClickListener(new OnLongClickListener() {
  			@Override
  			public boolean onLongClick(View v) {
  
  				Toast.makeText(MainActivity.this,
  						"I got a long press!", Toast.LENGTH_SHORT).show();
  				return false;
  			}
  		});
          setContentView(mLongPressView);
      }
  }

   

• LongPressEventDemo.rar (14.4 KB)
• 下载次数: 7

  http://elingwange.iteye.com/blog/1666741

   

  http://blog.youkuaiyun.com/eoeandroida/article/details/8308877
• http://www.open-open.com/lib/view/open1362710410109.html