GestureDetector- 滑屏手势方式实现

今天做的项目中，需要使用滑屏来调出一个界面，经过自己的尝试，结合网上的方法，成功实现了。

代码如下

package com.example.text;

import android.app.Activity;

import android.os.Bundle;

import android.view.GestureDetector;

import android.view.GestureDetector.OnGestureListener;

import android.view.Menu;

import android.view.MenuItem;

import android.view.MotionEvent;

import android.widget.TextView;

public class MainActivity extends Activity implements OnGestureListener {

     private GestureDetector mGestureDetector;

     private TextView tv;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        tv=(TextView) findViewById(R.id.tv);

//这个如果直接写一个this，会提示过时。另外，如果两个参数都写成this，会报错。原因不知
        mGestureDetector = new GestureDetector(MainActivity.this, this);

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.main, menu);

        return true;

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        // Handle action bar item clicks here. The action bar will

        // automatically handle clicks on the Home/Up button, so long

        // as you specify a parent activity in AndroidManifest.xml.

        int id = item.getItemId();

        if (id == R.id.action_settings) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

    @Override

    public boolean onTouchEvent(MotionEvent event) {

        // TODO Auto-generated method stub

     //通过event自动判断手势，回调相应的方法

    return mGestureDetector.onTouchEvent(event);

    }
//按下屏幕触发，打印的是坐标 
 @Override

    public boolean onDown(MotionEvent arg0) {

        // TODO Auto-generated method stub

        tv.setText(arg0.getX()+"    "+arg0.getY());

        return false;

    }
//滑动屏幕的时候触发，打印的分别是起点跟终点的坐标 
 @Override

    public boolean onFling(MotionEvent arg0, MotionEvent arg1, float arg2,

            float arg3) {

        // TODO Auto-generated method stub

        tv.setText("arg1.getX()="+arg1.getX()+"   arg0.getX()="+arg1.getY()+"     arg2="+arg2+"   arg3="+arg3);

        return true;

    }

    @Override

    public void onLongPress(MotionEvent arg0) {

        // TODO Auto-generated method stub

    }

    @Override

    public boolean onScroll(MotionEvent arg0, MotionEvent arg1, float arg2,

            float arg3) {

        // TODO Auto-generated method stub

        return false;

    }

    @Override

    public void onShowPress(MotionEvent arg0) {

        // TODO Auto-generated method stub

    }

    @Override

    public boolean onSingleTapUp(MotionEvent arg0) {

        // TODO Auto-generated method stub

        return false;

    }

}

这个类的使用步骤如下

1.定义手势类：private GestureDetector mGestureDetector;

2.初始化类：这个是跟其他控件设置监听一样的，有多种方法

　　1）匿名内部类：

mGestureDetector = new GestureDetector(MainActivity.this, new OnGestureListener() {

            @Override

            public boolean onSingleTapUp(MotionEvent arg0) {

                // TODO Auto-generated method stub

                return false;

            }

            @Override

            public void onShowPress(MotionEvent arg0) {

                // TODO Auto-generated method stub

            }

            @Override

            public boolean onScroll(MotionEvent arg0, MotionEvent arg1, float arg2,

                    float arg3) {

                // TODO Auto-generated method stub

                return false;

            }

            @Override

            public void onLongPress(MotionEvent arg0) {

                // TODO Auto-generated method stub

            }

            @Override

            public boolean onFling(MotionEvent arg0, MotionEvent arg1, float arg2,

                    float arg3) {

                // TODO Auto-generated method stub

                return false;

            }

            @Override

            public boolean onDown(MotionEvent arg0) {

                // TODO Auto-generated method stub

                return false;

            }

        });

　　2).直接让主类继承：

public class MainActivity extends Activity implements OnGestureListener{

}

　　3).内部类

 class MyOnGestureListener  implements OnGestureListener{

}

3.在onTouchEvent()事件中使用这个类

   @Override

    public boolean onTouchEvent(MotionEvent event) {

        // TODO Auto-generated method stub

     //通过event自动判断手势，回调相应的方法

    return mGestureDetector.onTouchEvent(event);

    }

不过，现在还有一点不是很明白，就是方法中的return false跟return true有什么区别

巴特西

GestureDetector- 滑屏手势方式实现

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