Android:触屏事件

Android触屏事件包含两种：

1）屏幕触屏事件：重写onTouchEvent(MotionEvent event)；

2）控件触屏事件：给控件注册触屏事件，setOnTouchEventListener(...)。

屏幕触屏事件

效果：

代码：

res/values/colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="red">#FF0000</color>

</resources>

res/layout/activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/tvPosition"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="30dp"
        android:textColor="@color/red" />

</RelativeLayout>

MainActivity.java

package com.example.helloword;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MotionEvent;
import android.widget.TextView;

public class MainActivity extends Activity {
    private TextView tvPosition;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.tvPosition = (TextView) this.findViewById(R.id.tvPosition);
    }

    @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 onTouchEvent(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();

        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            Log.i("Test", "fired onTouchEvent: DOWN. x=" + x + ",y=" + y);
            break;
        case MotionEvent.ACTION_MOVE:
            Log.i("Test", "fired onTouchEvent: MOVE. x=" + x + ",y=" + y);
            this.tvPosition.setText("x=" + x + ",y=" + y);
            break;
        case MotionEvent.ACTION_UP:
            Log.i("Test", "fired onTouchEvent: UP. x=" + x + ",y=" + y);
            break;
        }

        // 默认：返回值为false，表示该事件还未触发完成，将继续向上执行。
        return super.onTouchEvent(event);
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        // 当点击回退时，弹出该窗口（也就相当于关闭操作）
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            new AlertDialog.Builder(this).setTitle("是否退出？")
                    .setPositiveButton("确定", new OnClickListener() {
                        @Override
                        public void onClick(DialogInterface arg0, int arg1) {
                            finish();
                        }
                    }).setNegativeButton("取消", null).show();
            return true;
        }
        return super.onKeyUp(keyCode, event);
    }
}

备注：

1）监听触屏事件包含三个Action：Up/Down/Move;

2）默认覆盖屏幕事件返回值为false,表示该事件还未结束，将会继续向上触发。

控件触屏事件

1）只有在注册了setOnTouchEventListener事件的空间上触发事件时，才能响应触屏事件；

2）效果：

3）代码：

res/values/colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="red">#FF0000</color>
    <color name="yellow">#FFFF00</color>
</resources>

res/layout/activity_viewcontrollerontouchevent.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <View
        android:id="@+id/vTouchPanel"
        android:layout_width="wrap_content"
        android:layout_height="250dp"
        android:background="@color/yellow" />

    <TextView
        android:id="@+id/textViewPosition"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="@color/red" />

</LinearLayout>

/AndroidManifest.xml,将首页activity_main.xml修改为activity_viewcontrollerontouchevent.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.helloword"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.helloword.ViewControllerOnTouchEventActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

ViewControllerOnTouchEventActivity.java

 package com.example.helloword;

 import android.app.Activity;
 import android.os.Bundle;
 import android.view.MotionEvent;
 import android.view.View;
 import android.widget.TextView;

 public class ViewControllerOnTouchEventActivity extends Activity {
     private TextView textViewPosition;
     private View vTouchPanel;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_viewcontrollerontouchevent);
         this.textViewPosition = (TextView) this
                 .findViewById(R.id.textViewPosition);
         this.vTouchPanel = this.findViewById(R.id.vTouchPanel);

         this.vTouchPanel.setOnTouchListener(new View.OnTouchListener() {
             @Override
             public boolean onTouch(View view, MotionEvent motionEvent) {
                 if (motionEvent.getAction() == MotionEvent.ACTION_MOVE) {
                     textViewPosition.setText("x=" + motionEvent.getX() + ",y="
                             + motionEvent.getY());
                 }

                 // 离开该空间范围就完成事件，不再向上触发。
                 return true;
             }
         });
     }

 }