Easily implement Android lock screen function

package ; 
 
import ; 
 
/**
  * @author Zhang,Tianyou
  * @version November 20, 2014 9:51:42 pm
  *
  * Special broadcast recipient Receive Administrator permission broadcast
  */ 
 
public class MyAdmin extends DeviceAdminReceiver{ 
 
} 

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:andro 
  package="" 
  android:versionCode="1" 
  android:versionName="1.0" > 
 
  <uses-sdk 
    android:minSdkVersion="8" 
    android:targetSdkVersion="17" /> 
 
  <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="" /> 
 
        <category android:name="" /> 
      </intent-filter> 
    </activity> 
     
     <receiver 
      android:name=".MyAdmin" 
      android:description="@string/sample_device_admin_description" 
      android:label="@string/sample_device_admin" 
      android:permission=".BIND_DEVICE_ADMIN" > 
      <meta-data 
        android:name=".device_admin" 
        android:resource="@xml/device_admin_sample" /> 
 
      <intent-filter> 
        <action android:name=".DEVICE_ADMIN_ENABLED" /> 
      </intent-filter> 
    </receiver> 
  </application> 
 
</manifest> 

<device-admin xmlns:andro> 
 <uses-policies> 
  <limit-password /> 
  <watch-login /> 
  <reset-password /> 
  <force-lock /> 
  <wipe-data /> 
  <expire-password /> 
  <encrypted-storage /> 
  <disable-camera /> 
 </uses-policies> 
</device-admin> 

<string name="sample_device_admin_description">User administrator description information</string> 
<string name="sample_device_admin">Set management permissions</string> 

<RelativeLayout xmlns:andro 
  xmlns:tools="/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="" > 
 
   <Button 
    android:onClick="openAdmin" 
    android:layout_alignParentTop="true" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Enable Administrator Permissions" /> 
   
  <Button 
    android:onClick="lockcreen" 
    android:layout_centerInParent="true" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="One-click lock screen" /> 
 
  <Button 
    android:onClick="uninstall" 
    android:layout_alignParentBottom="true" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Uninstall the lock screen" /> 
</RelativeLayout> 

package ; 
 
import ; 
import ; 
import ; 
import ; 
import ; 
import ; 
import ; 
import ; 
 
public class MainActivity extends Activity { 
 
  /**
    * Equipment Policy Service
    */ 
  private DevicePolicyManager dpm; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    // TODO Auto-generated method stub 
    (savedInstanceState); 
    setContentView(.activity_main); 
    dpm = (DevicePolicyManager) getSystemService(DEVICE_POLICY_SERVICE); 
  } 
 
  /**
    * Lock screen
    *
    * @param view
    */ 
  public void lockcreen(View view) { 
    ComponentName who = new ComponentName(this, ); 
    // Determine whether administrator permissions have been enabled    if ((who)) { 
      // Lock screen      (); 
      // Set the screen password The first one is the password The second one is the additional parameters      ("123", 0); 
 
      // Clear data      // WIPE_EXTERNAL_STORAGE Clear sdcard data      // 0 Factory reset      //(DevicePolicyManager.WIPE_EXTERNAL_STORAGE); 
    } else { 
      // If not enabled      (, "Please enable administrator permission first!", Toast.LENGTH_SHORT) 
          .show(); 
    } 
  } 
   
 
  /**
    * Code enables management permissions
    *
    * @param view
    */ 
  public void openAdmin(View view) { 
    // Create an Intent Add Device Administrator    Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN); 
    // Activate MyAdmin broadcast to receive    ComponentName who = new ComponentName(this, ); 
 
    (DevicePolicyManager.EXTRA_DEVICE_ADMIN, who); 
    // Explain the benefits of enabling administrator privileges by users    (DevicePolicyManager.EXTRA_ADD_EXPLANATION, 
        "Open can lock the screen with one click to prevent it from touching"); 
    startActivity(intent); 
     
    (, "Administrator permissions are enabled!", Toast.LENGTH_SHORT).show(); 
  } 
 
  /**
    * Uninstall the current software. Device management data is special. Therefore, it cannot be uninstalled normally.
    */ 
 
  public void uninstall(View view) { 
    // 1. Clear administrator permissions first    ComponentName who = new ComponentName(this, 
        ); 
    (who); 
 
    // 2. Uninstallation of ordinary applications    Intent intent = new Intent(); 
    (""); 
    (""); 
    (("package:"+getPackageName())); 
    startActivity(intent); 
 
  } 
 
}