Android程序之一键锁屏

（1）布局文件activity_main.xml如下：

<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"
    tools:context=".MainActivity" >

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="openAdmin"
        android:text="开启管理员权限" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:onClick="lockscreen"
        android:text="一键锁屏" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:onClick="uninstall"
        android:text="卸载软件" />

</RelativeLayout>

（2）MainActivity.java

package com.xuliugen.lockscreen;

import com.itheima.lockscreen.R;

import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

    /**
     * 设备策略服务
     */
    private DevicePolicyManager dpm;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        dpm = (DevicePolicyManager) getSystemService(DEVICE_POLICY_SERVICE);

    }

    /**
     * 用代码去开启管理员
     */
    public void openAdmin(View view) {
        // 创建一个Intent
        Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
        // 我要激活谁
        ComponentName mDeviceAdminSample = new ComponentName(this,MyAdmin.class);

        intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN,mDeviceAdminSample);
        // 劝说用户开启管理员权限
        intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,"哥们开启我可以一键锁屏，你的按钮就不会经常失灵");
        startActivity(intent);
    }

    /**
     * 一键锁屏
     */
    public void lockscreen(View view) {
        ComponentName who = new ComponentName(this, MyAdmin.class);
        if (dpm.isAdminActive(who)) {
            dpm.lockNow();// 锁屏
            dpm.resetPassword("", 0);// 设置屏蔽密码

            // 清除Sdcard上的数据
            // dpm.wipeData(DevicePolicyManager.WIPE_EXTERNAL_STORAGE);
            // 恢复出厂设置
            // dpm.wipeData(0);
        } else {
            Toast.makeText(this, "还没有打开管理员权限", 1).show();
            return;
        }

    }

    /**
     * 卸载当前软件
     */

    public void uninstall(View view) {

        // 1.先清除管理员权限
        ComponentName mDeviceAdminSample = new ComponentName(this,
                MyAdmin.class);
        dpm.removeActiveAdmin(mDeviceAdminSample);
        // 2.普通应用的卸载
        Intent intent = new Intent();
        intent.setAction("android.intent.action.VIEW");
        intent.addCategory("android.intent.category.DEFAULT");
        intent.setData(Uri.parse("package:" + getPackageName()));
        startActivity(intent);
    }

}

（3）根据API文档可知，需要一个类继承DeviceAdminReceiver:

package com.xuliugen.lockscreen;

import android.app.admin.DeviceAdminReceiver;

/**
 * 特殊的广播接收者
 * 
 * @author xuliugen
 * 
 */
public class MyAdmin extends DeviceAdminReceiver {

}

（5）广播接受者的设置（清单文件）：

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

    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="16" />

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

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

        <!-- 广播接收者 -->
        <receiver
            android:name="com.xuliugen.lockscreen.MyAdmin"
            android:description="@string/sample_device_admin_description"
            android:label="@string/sample_device_admin"
            android:permission="android.permission.BIND_DEVICE_ADMIN" >
            <meta-data
                android:name="android.app.device_admin"
                android:resource="@xml/device_admin_sample" />

            <intent-filter>
                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
            </intent-filter>
        </receiver>
    </application>

</manifest>

运行效果：