Android 自定義View實現單擊和雙擊事件的方法

自定義View,

1. 自定義一個Runnable線程TouchEventCountThread ,  用來統計500ms內的點擊次數

2. 在MyView中的 onTouchEvent 中調用 上面的線程

3. 自定義一個Handler, 在TouchEventHandler 中 處理 統計到的點擊事件, 單擊, 雙擊, 三擊, 都可以處理

核心代碼如下： 

public class MyView extends View {

  ......

  // 統計500ms內的點擊次數
  TouchEventCountThread mInTouchEventCount = new TouchEventCountThread();
  // 根據TouchEventCountThread統計到的點擊次數, perform單擊還是雙擊事件
  TouchEventHandler mTouchEventHandler = new TouchEventHandler();

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        if (0 == mInTouchEventCount.touchCount) // 第一次按下時,開始統計
          postDelayed(mInTouchEventCount, 500);
        break;
      case MotionEvent.ACTION_UP:
        // 一次點擊事件要有按下和抬起, 有抬起必有按下, 所以只需要在ACTION_UP中處理
        mInTouchEventCount.touchCount++;
        // 如果是長按操作, 則Handler的消息,不能將touchCount置0, 需要特殊處理
        if(mInTouchEventCount.isLongClick) {
          mInTouchEventCount.touchCount = 0;
          mInTouchEventCount.isLongClick = false;
        }
        break;
      case MotionEvent.ACTION_MOVE:
        break;
      case MotionEvent.ACTION_CANCEL:
        break;
      default:
        break;
    }

    return super.onTouchEvent(event);
  }

  public class TouchEventCountThread implements Runnable {
    public int touchCount = 0;
    public boolean isLongClick = false;

    @Override
    public void run() {
      Message msg = new Message();
      if(0 == touchCount){ // long click
        isLongClick = true;
      } else {
        msg.arg1 = touchCount;
        mTouchEventHandler.sendMessage(msg);
        touchCount = 0;
      }
    }
  }

  public class TouchEventHandler extends Handler {

    @Override
    public void handleMessage(Message msg) {
      Toast.makeText(mContext, "touch " + msg.arg1 + " time.", Toast.LENGTH_SHORT).show();
    }
  }

  ......

}

包裝以後如下, 這樣就能在別的地方調用了：

public interface OnDoubleClickListener{
    void onDoubleClick(View v);
  }
  
  private OnDoubleClickListener mOnDoubleClickListener;

  public void setOnDoubleClickListener(MyView.OnDoubleClickListener l) {
    mOnDoubleClickListener = l;
  }

  public boolean performDoubleClick() {
    boolean result = false;
    if(mOnDoubleClickListener != null) {
      mOnDoubleClickListener.onDoubleClick(this);
      result = true;
    }
    return result;
  }

  public class TouchEventHandler extends Handler {

    @Override
    public void handleMessage(Message msg) {
      if(2 == msg.arg1)
        performDoubleClick();
    }
  }

在Activity中使用：

myView1.setOnDoubleClickListener(new MyView.OnDoubleClickListener() {
  @Override
  public void onDoubleClick(View v) {
  Toast.makeText(mContext,"double click", Toast.LENGTH_SHORT).show();
  }
});

全部代碼

MyView.java

package com.carloz.test.myapplication.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

import com.carloz.test.myapplication.R;

/**
 * Created by root on 15-11-9.
 */
public class MyView extends View {

  private Paint mPaint = new Paint();
  private boolean mNotDestroy = true;
  private int mCount = 0;
  private MyThread myThread;
  Bitmap bitmap;
  // attrs
  private String mText;
  private boolean mStartChange;
  Context mContext;


  public MyView(Context context) {
    super(context);
    init();
  }

  public MyView(Context context, AttributeSet attrs) {
    super(context, attrs);
    TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.MyView);
    mText = ta.getString(R.styleable.MyView_text);
    mStartChange = ta.getBoolean(R.styleable.MyView_startChange, false);
    // Log.d("ASDF", "mText=" + mText + ", mStartChange=" + mStartChange);
    ta.recycle();

    init();
  }

  @Override
  protected void onFinishInflate() {
    super.onFinishInflate();
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  }

  @Override
  protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
    super.onLayout(changed, left, top, right, bottom);
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    mPaint.setTextSize(50);
    canvas.drawText(mText + mCount++, 20f, 100f, mPaint);
    canvas.save();
    canvas.rotate(60, getWidth() / 2, getHeight() / 2);
    canvas.drawBitmap(bitmap, 20f, 50f, mPaint);
    canvas.restore();

    if (null == myThread) {
      myThread = new MyThread();
      myThread.start();
    }
  }

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

  @Override
  protected void onAttachedToWindow() {
    super.onAttachedToWindow();
    mNotDestroy = true;
  }

  @Override
  protected void onDetachedFromWindow() {
    mNotDestroy = false;
    super.onDetachedFromWindow();
  }

  // 統計500ms內的點擊次數
  TouchEventCountThread mInTouchEventCount = new TouchEventCountThread();
  // 根據TouchEventCountThread統計到的點擊次數, perform單擊還是雙擊事件
  TouchEventHandler mTouchEventHandler = new TouchEventHandler();

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        if (0 == mInTouchEventCount.touchCount) // 第一次按下時,開始統計
          postDelayed(mInTouchEventCount, 500);
        break;
      case MotionEvent.ACTION_UP:
        // 一次點擊事件要有按下和抬起, 有抬起必有按下, 所以只需要在ACTION_UP中處理
        mInTouchEventCount.touchCount++;
        // 如果是長按操作, 則Handler的消息,不能將touchCount置0, 需要特殊處理
        if(mInTouchEventCount.isLongClick) {
          mInTouchEventCount.touchCount = 0;
          mInTouchEventCount.isLongClick = false;
        }
        break;
      case MotionEvent.ACTION_MOVE:
        break;
      case MotionEvent.ACTION_CANCEL:
        break;
      default:
        break;
    }

    return super.onTouchEvent(event);
  }

  public class TouchEventCountThread implements Runnable {
    public int touchCount = 0;
    public boolean isLongClick = false;

    @Override
    public void run() {
      Message msg = new Message();
      if(0 == touchCount){ // long click
        isLongClick = true;
      } else {
        msg.arg1 = touchCount;
        mTouchEventHandler.sendMessage(msg);
        touchCount = 0;
      }
    }
  }

  public class TouchEventHandler extends Handler {

    @Override
    public void handleMessage(Message msg) {
      Toast.makeText(mContext, "touch " + msg.arg1 + " time.", Toast.LENGTH_SHORT).show();
    }
  }

  class MyThread extends Thread {

    @Override
    public void run() {
      super.run();
      while (mNotDestroy) {
        if (mStartChange) {
          postInvalidate();
          try {
            Thread.sleep(500);
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
        }
      }
    }
  }

  public void init() {
    mContext = getContext();
    bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
  }

  public void setText(String mText) {
    this.mText = mText;
  }

  public void setStartChange(boolean mStartChange) {
    this.mStartChange = mStartChange;
  }

  public boolean getStartChange() {
    return this.mStartChange;
  }
}

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <declare-styleable name="MyView">
    <attr name="text" format="string"/>
    <attr name="startChange" format="boolean"/>
  </declare-styleable>

</resources>

postDelayed方法最終是靠 Handler 的 postDelayed 方法 實現原理如下

public final boolean postDelayed(Runnable r, long delayMillis)
  {
    return sendMessageDelayed(getPostMessage(r), delayMillis);
  }

  public final boolean sendMessageDelayed(Message msg, long delayMillis)
  {
    if (delayMillis < 0) {
      delayMillis = 0;
    }
    return sendMessageAtTime(msg, SystemClock.uptimeMillis() + delayMillis);
  }

  public boolean sendMessageAtTime(Message msg, long uptimeMillis) {
    MessageQueue queue = mQueue;
    if (queue == null) {
      RuntimeException e = new RuntimeException(
          this + " sendMessageAtTime() called with no mQueue");
      Log.w("Looper", e.getMessage(), e);
      return false;
    }
    return enqueueMessage(queue, msg, uptimeMillis); // 然後在MessageQueue中會比較時間順序
  }

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