在實現鎖屏功能時能可能會出現這個問題出現.....這主要是因為鎖屏需要管理員的許可權.......

解決方法如下:

1、新建一個MyAdmin.java

package com.njupt.testrotate1;import android.app.admin.DeviceAdminReceiver;public class MyAdmin extends DeviceAdminReceiver {}

2、在清單檔案中如下配置:

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"
 
    package="com.njupt.testrotate1"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="8" />    <uses-permission android:name="android.permission.VIBRATE"/>    <application        android:allowBackup
 
="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="com.njupt.testrotate1.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="com.njupt.testrotate1.MyAdmin" >            <meta-data android:name="android.app.device_admin"                android:resource="@xml/my_admin"/>            <intent-filter >                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED"/>            </intent-filter>        </receiver>    </application></manifest>

3、在res目錄下新建xml/my_admin.xml

<?xml version="1.0" encoding="utf-8"?><device-admin xmlns:android="http://schemas.android.com/apk/res/android">    <!--     limit-password  設定密碼的規則    watch-login 監控螢幕解鎖嘗試次數    reset-password 更改螢幕解鎖密碼    force-lock 裝置自動鎖屏    wipe-data 刪除全部的資料         -->    <uses-policies>        <limit-password/>        <watch-login />        <reset-password />        <force-lock />        <wipe-data />    </uses-policies></device-admin>

4、在MainAcitivity中如下書寫:

private DevicePolicyManager devicePolicyManager; private boolean isAdminActive;devicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);  // 申請許可權  ComponentName componentName = new ComponentName(this, MyAdmin.class);  // 判斷該元件是否有系統管理員的許可權  isAdminActive = devicePolicyManager    .isAdminActive(componentName);    if(!isAdminActive){//這一句一定要有...   Intent intent = new Intent();   //指定動作   intent.setAction(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);   //指定給那個元件授權   intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);   startActivity(intent);  }if(isAdminActive){     Toast.makeText(this, "具有許可權,將進行鎖屏....", 1).show();     devicePolicyManager.lockNow();     devicePolicyManager.resetPassword("123321", 0);    }

package com.njupt.testrotate1;import android.os.Bundle;import android.os.Vibrator;import android.app.Activity;import android.app.Service;import android.app.admin.DevicePolicyManager;import android.content.ComponentName;import android.content.Context;import android.content.Intent;import android.hardware.Sensor;import android.hardware.SensorEvent;import android.hardware.SensorEventListener;import android.hardware.SensorManager;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity implements SensorEventListener { private Button clear; private TextView tv1; private SensorManager mSensorManager; private Vibrator vibrator; private int counter = 1; private DevicePolicyManager devicePolicyManager; private boolean isAdminActive; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.main);  mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);  vibrator = (Vibrator) getSystemService(Service.VIBRATOR_SERVICE);  // clear = (Button) findViewById(R.id.clear);  // clear.setOnClickListener(new Button.OnClickListener() {  //  // @Override  // public void onClick(View v) {  // clear.setText("現在給button賦值嘍....");  // }  // });  //  tv1 = (TextView) findViewById(R.id.tv1);  devicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);  // 申請許可權  ComponentName componentName = new ComponentName(this, MyAdmin.class);  // 判斷該元件是否有系統管理員的許可權  isAdminActive = devicePolicyManager    .isAdminActive(componentName);    if(!isAdminActive){   Intent intent = new Intent();   //指定動作   intent.setAction(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);   //指定給那個元件授權   intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);   startActivity(intent);  } } @Override protected void onResume() {  super.onResume();  mSensorManager.registerListener(this,    mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),    SensorManager.SENSOR_DELAY_GAME); } @Override protected void onStop() {  mSensorManager.unregisterListener(this);  super.onStop(); } @Override protected void onPause() {  mSensorManager.unregisterListener(this);  super.onPause(); } @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { } @Override public void onSensorChanged(SensorEvent event) {  int sensorType = event.sensor.getType();  float[] values = event.values;  float x = values[0];  float y = values[1];  if (sensorType == Sensor.TYPE_ACCELEROMETER) {   tv1.setText("現在的x軸是: " + x + " y軸是: " + y);   if (Math.abs(x) > 9.0 || Math.abs(y) > 9.0) {//    Toast.makeText(this, "現在的垂直方向已經超過了90度,將進行鎖屏", 1).show();    vibrator.vibrate(500);    System.out.println("...............isAdminActive: "      + isAdminActive);    if(isAdminActive){     Toast.makeText(this, "具有許可權,將進行鎖屏....", 1).show();     devicePolicyManager.lockNow();     devicePolicyManager.resetPassword("123321", 0);    }       }  } } @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; }}