Android 打开或者关闭手电筒，判断手电筒是否打开
- 打开或者关闭手电筒非常简单，代码如下：
val cameraManager =
App.getContext().getSystemService(Context.CAMERA_SERVICE) as CameraManager
try {
val flashLightStatus = SharedPreferencesUtil.flashLightStatus
cameraManager.setTorchMode("0", !flashLightStatus) // 0 或者 1
SharedPreferencesUtil.flashLightStatus = !flashLightStatus
} catch (e: CameraAccessException) {
e.printStackTrace()
}
- 但是手电筒打开有很多地方，为确保在其他地方打开的，在自己程序 也能关闭；
FlashlightController.java
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraManager;
import android.os.Handler;
import android.os.HandlerThread;
import android.text.TextUtils;
import android.util.Log;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
public class FlashlightController {
private static final String TAG = "FlashlightController";
private static final int DISPATCH_ERROR = 0;
private static final int DISPATCH_CHANGED = 1;
private static final int DISPATCH_AVAILABILITY_CHANGED = 2;
private CameraManager mCameraManager;
private Context mContext;
/**
* Call {@link #ensureHandler()} before using
*/
private Handler mHandler;
/**
* Lock on mListeners when accessing
*/
private final ArrayList<WeakReference<FlashlightListener>> mListeners = new ArrayList<>(1);
/**
* Lock on {@code this} when accessing
*/
private boolean mFlashlightEnabled;
private String mCameraId;
private boolean mTorchAvailable;
// battery low policy, add by [email protected] at 20180930 start +++
private final int LOW_BATTERY_THRESHOLD_FLASH = 15;// Low battery 15 for threshold flash, torch icon is grayed.
// private boolean mBatteryLow = false;
// end +++
public FlashlightController(Context context) {
mContext = context;
mCameraManager = (CameraManager) mContext.getSystemService(Context.CAMERA_SERVICE);
// registerReceiver();// add register battery intent for torch status, add by [email protected] at 20180930 +++
tryInitCamera();
}
// add battery intent for torch icon, add by [email protected] at 20180929 +++
// private void registerReceiver() {
// IntentFilter filter = new IntentFilter();
// filter.addAction(Intent.ACTION_BATTERY_CHANGED);
// mContext.registerReceiver(this, filter);
// }
// @Override
// public void onReceive(final Context context, Intent intent) {
// final String action = intent.getAction();
// if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
// int batteryLevel = intent.getIntExtra("level", 0);
// int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
// // BATTERY_STATUS_INVALID=0, BATTERY_STATUS_UNKNOWN=1, BATTERY_STATUS_CHARGING=2, BATTERY_STATUS_DISCHARGING=3, BATTERY_STATUS_NOT_CHARGING=4, BATTERY_STATUS_FULL=5
// int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, BatteryManager.BATTERY_STATUS_UNKNOWN);
//
// Log.i(TAG, "batteryLevel:" + batteryLevel + ", level:" + level + ", status:" + status + ", mBatteryLow:" + mBatteryLow);
// if (level <= LOW_BATTERY_THRESHOLD_FLASH) {
// mBatteryLow = true;
// } else {
// mBatteryLow = false;
// }
// }
// }
// end +++
private void tryInitCamera() {
try {
mCameraId = getCameraId();
} catch (Throwable e) {
Log.e(TAG, "Couldn't initialize.", e);
return;
}
Log.d(TAG, "tryInitCamera mCameraId =" + mCameraId);
if (mCameraId != null) {
ensureHandler();
mCameraManager.registerTorchCallback(mTorchCallback, mHandler);
}
}
public void setFlashlight(boolean enabled) {
boolean pendingError = false;
synchronized (this) {
if (mCameraId == null) return;
if (mFlashlightEnabled != enabled) {
mFlashlightEnabled = enabled;
try {
mCameraManager.setTorchMode(mCameraId, enabled);
} catch (CameraAccessException e) {
Log.e(TAG, "Couldn't set torch mode", e);
mFlashlightEnabled = false;
pendingError = true;
}
}
}
dispatchModeChanged(mFlashlightEnabled);
if (pendingError) {
dispatchError();
}
}
public boolean hasFlashlight() {
return mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
}
// add Toast for low battery level warning, by [email protected] 20190128 start +++
// public boolean isLowBattery() {
// return mBatteryLow;
// }
// end +++
public synchronized boolean isEnabled() {
return mFlashlightEnabled;
}
public synchronized boolean isAvailable() {
// torch icon should be unavailabe and grayed when battery level <= 15%, add by [email protected] at 20180930 start +++
// add Toast for low battery level warning, by [email protected] 20190128 start +++
// if (mBatteryLow)
// return false;
// end +++
// end +++
return mTorchAvailable;
}
public void addCallback(FlashlightListener l) {
synchronized (mListeners) {
Log.d(TAG, "addCallback mCameraId =" + mCameraId);
if (mCameraId == null) {
tryInitCamera();
}
cleanUpListenersLocked(l);
mListeners.add(new WeakReference<>(l));
l.onFlashlightAvailabilityChanged(mTorchAvailable);
l.onFlashlightChanged(mFlashlightEnabled);
}
}
public void removeCallback(FlashlightListener l) {
synchronized (mListeners) {
Log.d(TAG, "removeCallback mCameraId =" + mCameraId);
cleanUpListenersLocked(l);
}
}
private String getCameraId() throws CameraAccessException {
String[] ids = mCameraManager.getCameraIdList();
for (String id : ids) {
CameraCharacteristics c = mCameraManager.getCameraCharacteristics(id);
Boolean flashAvailable = c.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
Integer lensFacing = c.get(CameraCharacteristics.LENS_FACING);
if (flashAvailable != null && flashAvailable && lensFacing != null && lensFacing == CameraCharacteristics.LENS_FACING_BACK) {
return id;
}
}
return null;
}
private synchronized void ensureHandler() {
if (mHandler == null) {
HandlerThread thread = new HandlerThread(TAG, 1);
thread.start();
mHandler = new Handler(thread.getLooper());
}
}
private final CameraManager.TorchCallback mTorchCallback = new CameraManager.TorchCallback() {
@Override
public void onTorchModeUnavailable(String cameraId) {
if (TextUtils.equals(cameraId, mCameraId)) {
setCameraAvailable(false);
}
}
@Override
public void onTorchModeChanged(String cameraId, boolean enabled) {
Log.d(TAG, "onTorchModeChanged cameraId = " + cameraId + ",mCameraId=" + mCameraId + ",enabled=" + enabled);
if (TextUtils.equals(cameraId, mCameraId)) {
setCameraAvailable(true);
setTorchMode(enabled);
}
}
private void setCameraAvailable(boolean available) {
boolean changed;
synchronized (FlashlightController.this) {
changed = mTorchAvailable != available;
mTorchAvailable = available;
}
if (changed) {
Log.d(TAG, "dispatchAvailabilityChanged(" + available + ")");
dispatchAvailabilityChanged(available);
}
}
private void setTorchMode(boolean enabled) {
Log.d(TAG, "setTorchMode enabled=" + enabled);
boolean changed;
synchronized (FlashlightController.this) {
changed = mFlashlightEnabled != enabled;
mFlashlightEnabled = enabled;
}
if (changed) {
Log.d(TAG, "dispatchModeChanged(" + enabled + ")");
dispatchModeChanged(enabled);
}
}
};
private void dispatchModeChanged(boolean enabled) {
dispatchListeners(DISPATCH_CHANGED, enabled);
}
private void dispatchError() {
dispatchListeners(DISPATCH_CHANGED, false /* argument (ignored) */);
}
private void dispatchAvailabilityChanged(boolean available) {
dispatchListeners(DISPATCH_AVAILABILITY_CHANGED, available);
}
private void dispatchListeners(int message, boolean argument) {
synchronized (mListeners) {
final int N = mListeners.size();
boolean cleanup = false;
for (int i = 0; i < N; i++) {
FlashlightListener l = mListeners.get(i).get();
if (l != null) {
if (message == DISPATCH_ERROR) {
l.onFlashlightError();
} else if (message == DISPATCH_CHANGED) {
l.onFlashlightChanged(argument);
} else if (message == DISPATCH_AVAILABILITY_CHANGED) {
l.onFlashlightAvailabilityChanged(argument);
}
} else {
cleanup = true;
}
}
if (cleanup) {
cleanUpListenersLocked(null);
}
}
}
private void cleanUpListenersLocked(FlashlightListener listener) {
for (int i = mListeners.size() - 1; i >= 0; i--) {
FlashlightListener found = mListeners.get(i).get();
if (found == null || found == listener) {
mListeners.remove(i);
}
}
}
public interface FlashlightListener {
/**
* Called when the flashlight was turned off or on.
*
* @param enabled true if the flashlight is currently turned on.
*/
void onFlashlightChanged(boolean enabled);
/**
* Called when there is an error that turns the flashlight off.
*/
void onFlashlightError();
/**
* Called when there is a change in availability of the flashlight functionality
*
* @param available true if the flashlight is currently available.
*/
void onFlashlightAvailabilityChanged(boolean available);
}
}
初始化，
public class App extends Application {
private static App mInstance;
private FlashlightController flashlightController ;
@Override
public void onCreate() {
super.onCreate();
Log.d("App", "onCreate");
mInstance = this;
flashlightController=new FlashlightController(mInstance);
}
public static FlashlightController getFlashlightController() {
return mInstance.flashlightController;
}
}
使用：
@JvmStatic
fun turnOnOffFlashLight() {
val controller= App.getFlashlightController()
Log.d(TAG,"isEnabled= ${
controller.isEnabled}")
Log.d(TAG,"isAvailable= ${
controller.isAvailable}")
controller.setFlashlight( !controller.isEnabled)
}