使用DevicePolicyManager锁定屏幕

Question

我知道这不是第一次被问到的问题，但我找不到解决我的问题的方法。

下面是一些代码：

MainActivity.class：

package com.fromscratch.aside;


import android.app.admin.DeviceAdminReceiver;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;

public class MainActivity extends ActionBarActivity implements View.OnClickListener {

DevicePolicyManager mDPM;
ComponentName mAdminName;
protected static final int REQUEST_ENABLE = 0;
private Button bLockButton;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mAdminName = new ComponentName(MainActivity.this,MyAdmin.class);
    mDPM = (DevicePolicyManager)getSystemService(Context.DEVICE_POLICY_SERVICE);
    bLockButton = (Button)findViewById(R.id.lock_button);
    bLockButton.setOnClickListener(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.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();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(REQUEST_ENABLE == requestCode){
        System.out.println(mDPM.isAdminActive(mAdminName));
            super.onActivityResult(requestCode,resultCode,data);
    }
}

@Override
public void onClick(View v) {
    switch(v.getId()){
        case (R.id.lock_button):
            lockButtonClicked();
    }
}

private void lockButtonClicked(){
    if(!mDPM.isAdminActive(mAdminName)){

        Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
        intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN,mAdminName);
        startActivityForResult(intent,REQUEST_ENABLE);
    }
    else{
        mDPM.lockNow();
    }
}

public class MyAdmin extends DeviceAdminReceiver{

}
}

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.fromscratch.aside" >
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme">
        <activity
            android:name=".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>
        <receiver
            android:name=".MainActivity$MyAdmin"
            android:permission="android.permission.BIND_DEVICE_ADMIN">
            <meta-data
                android:name="android.app.aSide"
                android:resource="@xml/my_admin"/>
            <intent-filter>
                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED"/>
            </intent-filter>
        </receiver>
    </application>

</manifest>

my_admin.xml:

<device-admin xmlns:android="http://schemas.android.com/apk/res/android">
<uses-policies>
    <limit-password/>
    <watch-login/>
    <reset-password/>
    <wipe-data/>
    <force-lock/>
</uses-policies>

阅读了几个小时后，我还是不知道这段代码有什么问题。但我认为主要问题在于，当我在应用程序中点击锁定按钮时，我无法获得“接受管理员权限对话框”。

我尝试了从商店下载的另一个应用程序（tasker），以确保我的设备（Galaxy Note 4）没有问题。 --> 它可以工作（管理员权限对话框出现--> 确定-->屏幕已锁定）

也许你们能想到我在这里错过了什么。

先感谢您。

- Julian S

---

我忘记了：在lockButton点击方法中，mDPM.isAdminActive(mAdminName)始终为false。 - Julian S

那么问题是什么？ - kformeck

问题是，为什么我没有获得允许管理员权限的提示，以及为什么我无法从DevicePolicyManager执行locknow()命令。 - Julian S

Answer 1

我发现了几个问题:

1. 我没有看到DeviceAdminReceiver实现。

2. 你没有以任何方式启动设备管理设置。

我强烈建议您阅读此文档:

http://developer.android.com/guide/topics/admin/device-admin.html

这是我曾经开发的一个应用程序中锁定屏幕的快速示例：

private void lockScreen() {
    PowerManager pm = (PowerManager)getSystemService(Context.POWER_SERVICE);
    if (pm.isScreenOn()) {
        DevicePolicyManager policy = (DevicePolicyManager)
                getSystemService(Context.DEVICE_POLICY_SERVICE);
        try {
            policy.lockNow();
        } catch (SecurityException ex) {
            Toast.makeText(
                    this, 
                    "You must enable this app as a device administrator\n\n" +
                    "Please enable it and press back button to return here.",
                    Toast.LENGTH_LONG).show();
                ComponentName admin = new ComponentName(context, AdminReceiver.class);
                Intent intent = new Intent(
                    DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN).putExtra(
                        DevicePolicyManager.EXTRA_DEVICE_ADMIN, admin);
                context.startActivity(intent);
        }           
    }
}

AdminReceiver.java:

import android.app.admin.DeviceAdminReceiver;
import android.content.Context;
import android.content.Intent;
import android.support.v4.content.LocalBroadcastManager;

public class AdminReceiver extends DeviceAdminReceiver {
    public static final String ACTION_DISABLED = "device_admin_action_disabled";
    public static final String ACTION_ENABLED = "device_admin_action_enabled";

    @Override
    public void onDisabled(Context context, Intent intent) {
        super.onDisabled(context, intent);
        LocalBroadcastManager.getInstance(context).sendBroadcast(
            new Intent(ACTION_DISABLED));
    }
    @Override
    public void onEnabled(Context context, Intent intent) {
        super.onEnabled(context, intent);
        LocalBroadcastManager.getInstance(context).sendBroadcast(
            new Intent(ACTION_ENABLED));
    }
}

device_admin.xml:

<?xml version="1.0" encoding="utf-8"?>
<device-admin xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-policies>
        <force-lock />
    </uses-policies>
</device-admin>

并将此添加到您的清单中：

    <receiver
        android:name="com.example.lockthescreen.receivers.AdminReceiver"
        android:label="@string/device_admin"
        android:description="@string/device_admin_description"
        android:permission="android.permission.BIND_DEVICE_ADMIN">
        <meta-data
            android:name="android.app.device_admin"
            android:resource="@xml/device_admin" />
        <intent-filter>
            <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
        </intent-filter>
    </receiver>

希望这能帮助你。

顺祝商祺，

凯尔

- kformeck