你也可以使用下面的代码来关闭闪光灯。

Camera.Parameters params = mCamera.getParameters()
p.setFlashMode(Parameters.FLASH_MODE_OFF);
mCamera.setParameters(params);

根据我的经验，如果你的应用程序设计为纵向和横向工作，你需要声明变量凸轮为静态。否则，onDestroy()在切换方向时被调用，它会破坏它，但不会释放Camera，因此不可能再次重新打开它。

package com.example.flashlight;

import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.view.Menu;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

public static Camera cam = null;// has to be static, otherwise onDestroy() destroys it

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

public void flashLightOn(View view) {

    try {
        if (getPackageManager().hasSystemFeature(
                PackageManager.FEATURE_CAMERA_FLASH)) {
            cam = Camera.open();
            Parameters p = cam.getParameters();
            p.setFlashMode(Parameters.FLASH_MODE_TORCH);
            cam.setParameters(p);
            cam.startPreview();
        }
    } catch (Exception e) {
        e.printStackTrace();
        Toast.makeText(getBaseContext(), "Exception flashLightOn()",
                Toast.LENGTH_SHORT).show();
    }
}

public void flashLightOff(View view) {
    try {
        if (getPackageManager().hasSystemFeature(
                PackageManager.FEATURE_CAMERA_FLASH)) {
            cam.stopPreview();
            cam.release();
            cam = null;
        }
    } catch (Exception e) {
        e.printStackTrace();
        Toast.makeText(getBaseContext(), "Exception flashLightOff",
                Toast.LENGTH_SHORT).show();
    }
}
}

为了证明我必须画这条线

    <uses-permission android:name="android.permission.CAMERA" />

从http://developer.android.com/reference/android/hardware/Camera.html

上面建议的台词对我不起作用。

你也可以使用下面的代码来关闭闪光灯。

Camera.Parameters params = mCamera.getParameters()
p.setFlashMode(Parameters.FLASH_MODE_OFF);
mCamera.setParameters(params);

我得到了自动闪光与以下简单的三步。

我刚刚在Manifest.xml文件中添加了相机和Flash权限

< uses-permission android: name = " android.permission。相机" / > < uses-feature android: name = " android.hardware。相机" / > < uses-permission android: name = " android.permission.FLASHLIGHT " / > < uses-feature android: name = " android.hardware.camera。Flash " android:required="false" />

In your Camera Code do this way. //Open Camera Camera mCamera = Camera.open(); //Get Camera Params for customisation Camera.Parameters parameters = mCamera.getParameters(); //Check Whether device supports AutoFlash, If you YES then set AutoFlash List<String> flashModes = parameters.getSupportedFlashModes(); if (flashModes.contains(android.hardware.Camera.Parameters.FLASH_MODE_AUTO)) { parameters.setFlashMode(Parameters.FLASH_MODE_AUTO); } mCamera.setParameters(parameters); mCamera.startPreview(); Build + Run —> Now Go to Dim light area and Snap photo, you should get auto flash light if device supports.

在Marshmallow和上面的例子中，CameraManager的“setTorchMode()”似乎是答案。这对我来说很管用:

 final CameraManager mCameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
 CameraManager.TorchCallback torchCallback = new CameraManager.TorchCallback() {
     @Override
     public void onTorchModeUnavailable(String cameraId) {
         super.onTorchModeUnavailable(cameraId);
     }

     @Override
     public void onTorchModeChanged(String cameraId, boolean enabled) {
         super.onTorchModeChanged(cameraId, enabled);
         boolean currentTorchState = enabled;
         try {
             mCameraManager.setTorchMode(cameraId, !currentTorchState);
         } catch (CameraAccessException e){}



     }
 };

 mCameraManager.registerTorchCallback(torchCallback, null);//fires onTorchModeChanged upon register
 mCameraManager.unregisterTorchCallback(torchCallback);

2022年Kotlin版本:

fun Context.isFlashLightAvailable() = packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)

val Context.camaraManager: CameraManager get() = getSystemService(CameraManager::class.java)


fun Context.toggleFlashLight(on: Boolean) {
    camaraManager.run {

        val firstCameraWithFlash = cameraIdList.find { camera ->
            getCameraCharacteristics(camera).keys.any { it == FLASH_INFO_AVAILABLE }
        }

        firstCameraWithFlash?.let {
            runCatching { setTorchMode(it, on) }.onFailure { Timber.e(it, "Error setTorchMode") }
        } ?: Timber.e(Throwable("toggleFlashLight"), "Camera with flash not found")

    }
}

或者用一个返回结果的挂起函数

suspend fun Context.toggleFlashLightWithResult(on: Boolean): Boolean {
    return suspendCancellableCoroutine { cont ->
        runCatching {
            camaraManager.run {

                val firstCameraWithFlash = cameraIdList.find { camera ->
                    getCameraCharacteristics(camera).keys.any { it == FLASH_INFO_AVAILABLE }
                }

                val callback = object : CameraManager.TorchCallback() {
                    override fun onTorchModeChanged(cameraId: String, enabled: Boolean) {
                        super.onTorchModeChanged(cameraId, enabled)
            
                       if (cont.isActive) cont.resume(enabled)
                    }
                }

                if (firstCameraWithFlash == null) {
                    Timber.e(Throwable("toggleFlashLight"), "Camera with flash not found")
                    cont.resume(false)
                } else {
                    Timber.tag("~!").d("firstCameraWithFlash: $firstCameraWithFlash")
                    setTorchMode(firstCameraWithFlash, on)
                    registerTorchCallback(mainExecutor, callback)
                }

                cont.invokeOnCancellation { unregisterTorchCallback(callback) }
            }
        }
            .onFailure { Timber.e(it, "Error toggleFlashLight") }

    }
}