我正在尝试创建一个禁用摄像头的应用程序，我正在尝试SDK中的Device Admin示例，它在模拟器上工作正常，但在设备上，app force关闭项目点击并显示NoSuchmethod错误。
代码段
public static class AdminSampleFragment extends PreferenceFragment
implements OnPreferenceChangeListener, OnPreferenceClickListener{
// Useful instance variables
protected DeviceAdmin mActivity;
protected DevicePolicyManager mDPM;
protected ComponentName mDeviceAdminSample;
protected boolean mAdminActive;
// Optional shared UI
private PreferenceScreen mSetPassword;
private EditTextPreference mResetPassword;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Retrieve the useful instance variables
mActivity = (DeviceAdmin) getActivity();
mDPM = mActivity.mDPM;
mDeviceAdminSample = mActivity.mDeviceAdminSample;
mAdminActive = mActivity.isActiveAdmin();
// Configure the shared UI elements (if they exist)
mResetPassword = (EditTextPreference) findPreference(KEY_RESET_PASSWORD);
mSetPassword = (PreferenceScreen) findPreference(KEY_SET_PASSWORD);
if (mResetPassword != null) {
mResetPassword.setOnPreferenceChangeListener(this);
}
if (mSetPassword != null) {
mSetPassword.setOnPreferenceClickListener(this);
}
}
@Override
public void onResume() {
super.onResume();
mAdminActive = mActivity.isActiveAdmin();
reloadSummaries();
// Resetting the password via API is available only to active admins
if (mResetPassword != null) {
mResetPassword.setEnabled(mAdminActive);
}
}
/**
* Called automatically at every onResume. Should also call explicitly any time a
* policy changes that may affect other policy values.
*/
protected void reloadSummaries() {
if (mSetPassword != null) {
if (mAdminActive) {
// Show password-sufficient status under Set Password button
boolean sufficient = mDPM.isActivePasswordSufficient();
mSetPassword.setSummary(sufficient ?
R.string.password_sufficient : R.string.password_insufficient);
} else {
mSetPassword.setSummary(null);
}
}
}
@Override
public boolean onPreferenceClick(Preference preference) {
if (mSetPassword != null && preference == mSetPassword) {
Intent intent = new Intent(DevicePolicyManager.ACTION_SET_NEW_PASSWORD);
startActivity(intent);
return true;
}
return false;
}
@Override
public boolean onPreferenceChange(Preference preference, Object newValue) {
if (mResetPassword != null && preference == mResetPassword) {
doResetPassword((String)newValue);
return true;
}
return false;
}
/**
* This is dangerous, so we prevent automated tests from doing it, and we
* remind the user after we do it.
*/
private void doResetPassword(String newPassword) {
if (alertIfMonkey(mActivity, R.string.monkey_reset_password)) {
return;
}
mDPM.resetPassword(newPassword, DevicePolicyManager.RESET_PASSWORD_REQUIRE_ENTRY);
AlertDialog.Builder builder = new AlertDialog.Builder(mActivity);
String message = mActivity.getString(R.string.reset_password_warning, newPassword);
builder.setMessage(message);
builder.setPositiveButton(R.string.reset_password_ok, null);
builder.show();
}
/**
* Simple helper for summaries showing local & global (aggregate) policy settings
*/
protected String localGlobalSummary(Object local, Object global) {
return getString(R.string.status_local_global, local, global);
}
}
/**
* PreferenceFragment for "general" preferences.
*/
public static class GeneralFragment extends AdminSampleFragment
implements OnPreferenceChangeListener {
// UI elements
private CheckBoxPreference mEnableCheckbox;
private CheckBoxPreference mDisableCameraCheckbox;
private CheckBoxPreference mDisableKeyguardWidgetsCheckbox;
private CheckBoxPreference mDisableKeyguardSecureCameraCheckbox;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.device_admin_general);
mEnableCheckbox = (CheckBoxPreference) findPreference(KEY_ENABLE_ADMIN);
mEnableCheckbox.setOnPreferenceChangeListener(this);
mDisableCameraCheckbox = (CheckBoxPreference) findPreference(KEY_DISABLE_CAMERA);
mDisableCameraCheckbox.setOnPreferenceChangeListener(this);
mDisableKeyguardWidgetsCheckbox =
(CheckBoxPreference) findPreference(KEY_DISABLE_KEYGUARD_WIDGETS);
mDisableKeyguardWidgetsCheckbox.setOnPreferenceChangeListener(this);
mDisableKeyguardSecureCameraCheckbox =
(CheckBoxPreference) findPreference(KEY_DISABLE_KEYGUARD_SECURE_CAMERA);
mDisableKeyguardSecureCameraCheckbox.setOnPreferenceChangeListener(this);
}
// At onResume time, reload UI with current values as required
@Override
public void onResume() {
super.onResume();
mEnableCheckbox.setChecked(mAdminActive);
enableDeviceCapabilitiesArea(mAdminActive);
if (mAdminActive) {
mDPM.setCameraDisabled(mDeviceAdminSample, mDisableCameraCheckbox.isChecked());
mDPM.setKeyguardDisabledFeatures(mDeviceAdminSample, createKeyguardDisabledFlag());
reloadSummaries();
}
}
int createKeyguardDisabledFlag() {
int flags = DevicePolicyManager.KEYGUARD_DISABLE_FEATURES_NONE;
flags |= mDisableKeyguardWidgetsCheckbox.isChecked() ?
DevicePolicyManager.KEYGUARD_DISABLE_WIDGETS_ALL : 0;
flags |= mDisableKeyguardSecureCameraCheckbox.isChecked() ?
DevicePolicyManager.KEYGUARD_DISABLE_SECURE_CAMERA : 0;
return flags;
}
@Override
public boolean onPreferenceChange(Preference preference, Object newValue) {
if (super.onPreferenceChange(preference, newValue)) {
return true;
}
boolean value = (Boolean) newValue;
if (preference == mEnableCheckbox) {
if (value != mAdminActive) {
if (value) {
// Launch the activity to have the user enable our admin.
Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, mDeviceAdminSample);
intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,
mActivity.getString(R.string.add_admin_extra_app_text));
startActivityForResult(intent, REQUEST_CODE_ENABLE_ADMIN);
// return false - don't update checkbox until we're really active
return false;
} else {
mDPM.removeActiveAdmin(mDeviceAdminSample);
enableDeviceCapabilitiesArea(false);
mAdminActive = false;
}
}
} else if (preference == mDisableCameraCheckbox) {
mDPM.setCameraDisabled(mDeviceAdminSample, value);
reloadSummaries();
} else if (preference == mDisableKeyguardWidgetsCheckbox
|| preference == mDisableKeyguardSecureCameraCheckbox) {
mDPM.setKeyguardDisabledFeatures(mDeviceAdminSample, createKeyguardDisabledFlag());
reloadSummaries();
}
return true;
}
@Override
protected void reloadSummaries() {
super.reloadSummaries();
String cameraSummary = getString(mDPM.getCameraDisabled(mDeviceAdminSample)
? R.string.camera_disabled : R.string.camera_enabled);
mDisableCameraCheckbox.setSummary(cameraSummary);
int disabled = mDPM.getKeyguardDisabledFeatures(mDeviceAdminSample);
String keyguardWidgetSummary = getString(
(disabled & DevicePolicyManager.KEYGUARD_DISABLE_WIDGETS_ALL) != 0 ?
R.string.keyguard_widgets_disabled : R.string.keyguard_widgets_enabled);
mDisableKeyguardWidgetsCheckbox.setSummary(keyguardWidgetSummary);
String keyguardSecureCameraSummary = getString(
(disabled & DevicePolicyManager.KEYGUARD_DISABLE_SECURE_CAMERA) != 0 ?
R.string.keyguard_secure_camera_disabled : R.string.keyguard_secure_camera_enabled);
mDisableKeyguardSecureCameraCheckbox.setSummary(keyguardSecureCameraSummary);
}
/** Updates the device capabilities area (dis/enabling) as the admin is (de)activated */
private void enableDeviceCapabilitiesArea(boolean enabled) {
mDisableCameraCheckbox.setEnabled(enabled);
mDisableKeyguardWidgetsCheckbox.setEnabled(enabled);
mDisableKeyguardSecureCameraCheckbox.setEnabled(enabled);
}
}
logcat的
05-06 00:19:00.797: E/AndroidRuntime(9614): FATAL EXCEPTION: main
05-06 00:19:00.797: E/AndroidRuntime(9614): java.lang.NoSuchMethodError: android.app.admin.DevicePolicyManager.getKeyguardDisabledFeatures
05-06 00:19:00.797: E/AndroidRuntime(9614): at com.example.deviceadmin.DeviceAdmin$GeneralFragment.reloadSummaries(DeviceAdmin.java:317)
05-06 00:19:00.797: E/AndroidRuntime(9614): at com.example.deviceadmin.DeviceAdmin$AdminSampleFragment.onResume(DeviceAdmin.java:159)
05-06 00:19:00.797: E/AndroidRuntime(9614): at com.example.deviceadmin.DeviceAdmin$GeneralFragment.onResume(DeviceAdmin.java:256)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:877)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1018)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.FragmentManagerImpl.dispatchResume(FragmentManager.java:1810)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.Activity.performResume(Activity.java:4549)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2461)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2499)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1997)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.ActivityThread.access$600(ActivityThread.java:127)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.os.Handler.dispatchMessage(Handler.java:99)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.os.Looper.loop(Looper.java:137)
05-06 00:19:00.797: E/AndroidRuntime(9614): at android.app.ActivityThread.main(ActivityThread.java:4448)
05-06 00:19:00.797: E/AndroidRuntime(9614): at java.lang.reflect.Method.invokeNative(Native Method)
05-06 00:19:00.797: E/AndroidRuntime(9614): at java.lang.reflect.Method.invoke(Method.java:511)
05-06 00:19:00.797: E/AndroidRuntime(9614): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:823)
05-06 00:19:00.797: E/AndroidRuntime(9614): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:590)
05-06 00:19:00.797: E/AndroidRuntime(9614): at dalvik.system.NativeStart.main(Native Method)
请帮忙。 ！很长一段时间以来，我的问题没有得到令人满意的答案:(
提前致谢
答案 0 :(得分：2)
虽然之前添加了一些Device Admin API，但特定方法getKeyguardDisabledFeatures()仅在API 17中添加，即android Android 4.2或JELLY_BEAN_MR1以及此写作时发布的最新版本。
因此，您将无法在ICS测试设备上使用该方法，或者截至2013年5月用户手中拥有的许多方法。
据推测，您的成功测试是在运行4.2或4.2.2
的模拟器上进行的