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我被困在這個ClassCastException錯誤一段時間了，任何人都可以幫忙看一下嗎？我基本上試圖通過擴展DeviceAdminReceiver來遵循android設備管理示例。我基本上把所有東西都剝離了，只是想測試lockNow（）函數。Android/Java ClassCastException錯誤
這是我的代碼：
package com.example.locknow;
public class LockNow extends DeviceAdminReceiver {
void showToast(Context context, CharSequence msg){
Toast.makeText(context, "Lock_Now App: " + msg, Toast.LENGTH_SHORT).show();
}
@Override
public void onEnabled(Context context, Intent intent){
showToast(context, "enabled");
}
@Override
public void onDisabled(Context context, Intent intent){
showToast(context, "disabled");
}
public static class Controller extends Activity {
static final int REQUEST_CODE_ENABLE_ADMIN = 1;
DevicePolicyManager mDPM;
ActivityManager mAM;
ComponentName mLockNow;
Button mEnableButton;
Button mDisableButton;
Button mForceLockButton;
/** Called when the activity is first created. */
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDPM = (DevicePolicyManager)getSystemService(Context.DEVICE_POLICY_SERVICE);
mAM = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
mLockNow = new ComponentName(Controller.this, LockNow.class);
setContentView(R.layout.main);
mEnableButton = (Button)findViewById(R.id.enable_button);
mEnableButton.setOnClickListener(mEnableListener);
mDisableButton = (Button)findViewById(R.id.disable_button);
mDisableButton.setOnClickListener(mDisableListener);
mForceLockButton = (Button)findViewById(R.id.force_lock_button);
mForceLockButton.setOnClickListener(mForceLockListener);
}
void updateButtonStates(){
boolean active = mDPM.isAdminActive(mLockNow);
if (active) {
mEnableButton.setEnabled(false);
mDisableButton.setEnabled(true);
mForceLockButton.setEnabled(true);
} else {
mEnableButton.setEnabled(true);
mDisableButton.setEnabled(false);
mForceLockButton.setEnabled(false);
}
}
private OnClickListener mEnableListener = new OnClickListener(){
public void onClick(View v){
Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, mLockNow);
intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "additional text");
startActivityForResult(intent, REQUEST_CODE_ENABLE_ADMIN);
}
};
private OnClickListener mDisableListener = new OnClickListener(){
public void onClick(View v){
mDPM.removeActiveAdmin(mLockNow);
updateButtonStates();
}
};
private OnClickListener mForceLockListener = new OnClickListener(){
public void onClick(View v){
boolean active = mDPM.isAdminActive(mLockNow);
if (active){
mDPM.lockNow();
}
}
};
}
}
這是明顯的：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.locknow"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.BIND_DEVICE_ADMIN" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".LockNow"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".LockNow$Controller">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.SAMPLE_CODE" />
</intent-filter>
</activity>
<receiver android:name=".LockNow"
android:label="@string/sample_lock_now"
android:permission="android.permission.BIND_DEVICE_ADMIN">
<intent-filter>
<action android:name="android.action.DEVICE_ADMIN_ENABLED" />
</intent-filter>
</receiver>
</application>
</manifest>
而且RU ntime錯誤：
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): FATAL EXCEPTION: main
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.locknow/com.example.locknow.LockNow}: java.lang.ClassCastException: com.example.locknow.LockNow
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.os.Handler.dispatchMessage(Handler.java:99)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.os.Looper.loop(Looper.java:123)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.app.ActivityThread.main(ActivityThread.java:4627)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at java.lang.reflect.Method.invokeNative(Native Method)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at java.lang.reflect.Method.invoke(Method.java:521)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at dalvik.system.NativeStart.main(Native Method)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): Caused by: java.lang.ClassCastException: com.example.locknow.LockNow
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
04-27 04:02:47.785: ERROR/AndroidRuntime(1553): ... 11 more
我是Java和Android的新手，任何幫助非常感謝！ 謝謝， -J