package com.example.screendemo;
 
import android.app.admin.DeviceAdminReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
 
/**
 * MyDeviceAdminReceiver類
 * 繼承自DeviceAdminReceiver，用于接收設(shè)備管理事件。
 */
public class MyDeviceAdminReceiver extends DeviceAdminReceiver {
 
    @Override
    public void onEnabled(Context context, Intent intent) {
        Toast.makeText(context, "設(shè)備管理員已激活", Toast.LENGTH_SHORT).show();
    }
 
    @Override
    public void onDisabled(Context context, Intent intent) {
        Toast.makeText(context, "設(shè)備管理員已停用", Toast.LENGTH_SHORT).show();
    }
}

package com.example.screendemo;
 
import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
 
/**
 * MainActivity類
 * 實(shí)現(xiàn)滅屏功能，檢測設(shè)備管理員狀態(tài)，并通過DevicePolicyManager調(diào)用lockNow()滅屏。
 */
public class MainActivity extends Activity {
 
    private static final int REQUEST_CODE_ENABLE_ADMIN = 1;
 
    private DevicePolicyManager devicePolicyManager;
    private ComponentName compName;
    private Button btnEnableAdmin;
    private Button btnLockScreen;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        // 初始化設(shè)備管理器與組件名
        devicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
        compName = new ComponentName(this, MyDeviceAdminReceiver.class);
 
        btnEnableAdmin = findViewById(R.id.btn_enable_admin);
        btnLockScreen = findViewById(R.id.btn_lock_screen);
 
        // 檢查設(shè)備管理員是否激活
        updateButtonState();
 
        // 按鈕：激活設(shè)備管理員
        btnEnableAdmin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!devicePolicyManager.isAdminActive(compName)) {
                    // 創(chuàng)建激活設(shè)備管理員的Intent
                    Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
                    intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, compName);
                    intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,
                            "需要激活設(shè)備管理員權(quán)限以實(shí)現(xiàn)滅屏功能");
                    startActivityForResult(intent, REQUEST_CODE_ENABLE_ADMIN);
                } else {
                    Toast.makeText(MainActivity.this, "設(shè)備管理員已激活", Toast.LENGTH_SHORT).show();
                }
            }
        });
 
        // 按鈕：滅屏（鎖屏）
        btnLockScreen.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
 
                if (devicePolicyManager.isAdminActive(compName)) {
                    // 調(diào)用lockNow()立即鎖屏
                    devicePolicyManager.lockNow();
                } else {
                    Toast.makeText(MainActivity.this, "請先激活設(shè)備管理員權(quán)限", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
 
    /**
     * 更新按鈕狀態(tài)：根據(jù)設(shè)備管理員是否激活決定啟用滅屏按鈕
     */
    private void updateButtonState() {
        if (devicePolicyManager.isAdminActive(compName)) {
            btnEnableAdmin.setEnabled(false);
            btnLockScreen.setEnabled(true);
        } else {
            btnEnableAdmin.setEnabled(true);
            btnLockScreen.setEnabled(false);
        }
    }
 
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_CODE_ENABLE_ADMIN) {
            updateButtonState();
        }
        super.onActivityResult(requestCode, resultCode, data);
    }
}

<!-- res/layout/activity_main.xml -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:gravity="center"
    android:padding="16dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
 
    <!-- 按鈕：激活設(shè)備管理員權(quán)限 -->
    <Button
        android:id="@+id/btn_enable_admin"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="激活設(shè)備管理員" />
 
    <!-- 按鈕：滅屏 -->
    <Button
        android:id="@+id/btn_lock_screen"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="滅屏"
        android:layout_marginTop="20dp"/>
</LinearLayout>

<!-- AndroidManifest.xml -->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.screendemo">
 
    <!-- 需要聲明設(shè)備管理權(quán)限 -->
    <uses-permission android:name="android.permission.BIND_DEVICE_ADMIN" />
 
    <application
        android:allowBackup="true"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
 
        <!-- 注冊DeviceAdminReceiver -->
        <receiver
            android:name=".MyDeviceAdminReceiver"
            android:label="@string/app_name"
            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>

<!-- res/xml/device_admin_sample.xml -->
<device-admin xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 可以在這里定義需要的設(shè)備管理策略，本例僅需要鎖屏功能 -->
    <uses-policies>
        <force-lock />
    </uses-policies>
</device-admin>