看到很多刚学习的同志都很纠结按照 上很多代码的实现方法都打开不了闪光灯，确实刚开始也有同感滴啦！希望能给你们一些思路！
废话不多说先上几张图片(有图有真像哦！！！！！！！)
思路：开启闪光灯的方法
我是这样做的
package com.cai.helloworld;
import java.io.IOException;
import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class CameraPreview extends SurfaceView implements
SurfaceHolder.Callback {
private Camera mCamera;
private SurfaceHolder mHolder;
public static final String TAG = “CameraPreview”;
public CameraPreview(Context context) {
super(context);
}
@SuppressWarnings(“deprecation”)
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the
// preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, “Error setting camera preview: ” + e.getMessage());
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e) {
Log.d(TAG, “Error starting camera preview: ” + e.getMessage());
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
}
获取CameraPreview后就可以对闪光灯进行操作
下面就是手电筒Demo的例子：
package com.cai.helloworld;
import java.util.List;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.provider.Settings;
import android.app.Activity;
import android.content.ContentResolver;
import android.content.Context;
import android.content.pm.PackageManager;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.FrameLayout;
import android.widget.ImageButton;
import android.widget.Toast;
public class MainActivity extends Activity {
protected static final String TAG = “>>>>>>>MainActivity”;
private Camera mCamera;
private CameraPreview mPreview;
private FrameLayout preview;
private boolean isopent;
private boolean isCameraExist;
private ImageButton captureButton;
private int defualtLigth;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
defualtLigth = getScreenBrightness(this);
isCameraExist = checkCameraHardware(this);
if (isCameraExist) {
controlFlashLigth();
} else {
Toast.makeText(this, “您的设备没有照相功能或者此功能不可用”, Toast.LENGTH_LONG)
.show();
}
}
public void controlFlashLigth() {
// Create an instance of Camera
captureButton = (ImageButton) findViewById(R.id.button_capture);
mCamera = getCameraInstance();
// Create our Preview view and set it as the content of our
// activity.
mPreview = new CameraPreview(this, mCamera);
preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
preview.setVisibility(View.INVISIBLE);
captureButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (!isopent) {
v.setBackgroundResource(R.drawable.flashlight_on);
Toast.makeText(getApplicationContext(), “手电筒已开启”,
Toast.LENGTH_SHORT)
.show();
turnLightOn(mCamera);
isopent = true;
} else {
v.setBackgroundResource(R.drawable.flashlight_off);
Toast.makeText(getApplicationContext(), “手电筒已关闭”,
Toast.LENGTH_SHORT).show();
turnLightOFF(mCamera);
isopent = false;
}
}
});
}
/** A safe way to get an instance of the Camera object. */
public static Camera getCameraInstance() {
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
} catch (Exception e) {
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
/** Check if this device has a camera */
public boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
@Override
protected void onResume() {
super.onResume();
Log.e(TAG, “onResume>>>>>runtime”);
}
@Override
protected void onPause() {
super.onPause();
Log.e(TAG, “onPause>>>>>runtime”);
}
@Override
protected void onDestroy() {
super.onDestroy();
Log.e(TAG, “onDestroy>>>>>runtime”);
releaseCamera();
}
@Override
protected void onStop() {
super.onStop();
Log.e(TAG, “HomeANXIALE>>>onStop>>>>>runtime”);
}
private void releaseCamera() {
if (mCamera != null) {
mCamera.release(); // release the camera for other applications
mCamera = null;
}
}
public void turnLightOn(Camera mCamera) {
if (mCamera == null) {
return;
}
Parameters parameters = mCamera.getParameters();
if (parameters == null) {
return;
}
List flashModes = parameters.getSupportedFlashModes();
// Check if camera flash exists
if (flashModes == null) {
// Use the screen as a flashlight (next best thing)
captureButton.setBackgroundColor(this.getResources().getColor(
R.color.white));
setBrightness(this, 255);
return;
}
String flashMode = parameters.getFlashMode();
if (!Parameters.FLASH_MODE_TORCH.equals(flashMode)) {
// Turn on the flash
if (flashModes.contains(Parameters.FLASH_MODE_TORCH)) {
parameters.setFlashMode(Parameters.FLASH_MODE_TORCH);
mCamera.setParameters(parameters);
} else {
}
}
}
public void turnLightOFF(Camera mCamera) {
if (mCamera == null) {
return;
}
Parameters parameters = mCamera.getParameters();
if (parameters == null) {
return;
}
List flashModes = parameters.getSupportedFlashModes();
// Check if camera flash exists
if (flashModes == null) {
setBrightness(this, defualtLigth);
// Use the screen as a flashlight (next best thing)
return;
}
String flashMode = parameters.getFlashMode();
if (!flashMode.equals(Parameters.FLASH_MODE_OFF)) {
// Turn on the flash
if (flashModes.contains(Parameters.FLASH_MODE_OFF)) {
parameters.setFlashMode(Parameters.FLASH_MODE_OFF);
mCamera.setParameters(parameters);
} else {
}
}
}
/**
* 获取屏幕的亮度
*
* @param activity
* @return
*/
public static int getScreenBrightness(Activity activity) {
int nowBrightnessValue = 0;
ContentResolver resolver = activity.getContentResolver();
try {
nowBrightnessValue = android.provider.Settings.System.getInt(
resolver, Settings.System.SCREEN_BRIGHTNESS);
} catch (Exception e) {
e.printStackTrace();
}
return nowBrightnessValue;
}
/**
* 设置屏幕的亮度
*
* @param activity
* @return
*/
public static void setBrightness(Activity activity, int brightness) {
// Settings.System.putInt(activity.getContentResolver(),
// Settings.System.SCREEN_BRIGHTNESS_MODE,
// Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
lp.screenBrightness = Float.valueOf(brightness) * (1f / 255f);
// lp.screenBrightness =(brightness) * (1f / 255f);
activity.getWindow().setAttributes(lp);
}
｝
接下来就是新建一个布局文件activity_main.xml
布局中用到Framelayout,首先camera_preview用于获取camerapreview,之后用ImageButton对其进行覆盖。
android:layout_width=”fill_parent”
android:layout_height=”fill_parent”
android:orientation=”vertical” >
android:id=”@+id/camera_preview”
android:layout_width=”fill_parent”
android:layout_height=”fill_parent” />
android:id=”@+id/button_capture”
android:layout_width=”fill_parent”
android:layout_height=”fill_parent”
android:background=”@drawable/flashlight_off”
android:layout_gravity=”center” />
第一次写这个也不知道要说些什么，有什么看不懂的可以留言提问，会及时回答的
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