android 手电筒的实现
android手机用闪光灯做成手电筒的应用非常多,可是有的不能用。
后来发现是除了把 camera device的 flashmode设置成torch外还要打开预览:
以下是代码:
MainActivity.java
package com.android.flashlight; import android.app.Activity; import android.os.Bundle; import android.view.MotionEvent; import android.widget.ImageView; public class MainActivity extends Activity{ private FlashlightSurface mSurface; private ImageView mImageView; private boolean isFlashlightOn = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Contants.LogI("MainActivity: onCreate()"); mSurface = (FlashlightSurface) findViewById(R.id.surfaceview); mImageView = (ImageView) findViewById(R.id.image); } @Override public boolean onTouchEvent(MotionEvent event) { if(MotionEvent.ACTION_UP == event.getAction()){ Contants.LogI("MainActivity: onTouchEvent() : ACTION_UP"); if(isFlashlightOn){ mSurface.setFlashlightSwitch(false); isFlashlightOn = false; mImageView.setImageResource(R.drawable.flashlight_off); }else{ mSurface.setFlashlightSwitch(true); isFlashlightOn = true; mImageView.setImageResource(R.drawable.flashlight_on); } } return super.onTouchEvent(event); } }
FlashlightSurface.java
package com.android.flashlight; import android.content.Context; import android.graphics.PixelFormat; import android.hardware.Camera; import android.util.AttributeSet; import android.view.SurfaceHolder; import android.view.SurfaceView; public class FlashlightSurface extends SurfaceView implements SurfaceHolder.Callback{ private SurfaceHolder mHolder; private Camera mCameraDevices; private Camera.Parameters mParameters; public FlashlightSurface(Context context, AttributeSet attrs) { super(context, attrs); Contants.LogI("FlashlightSurface"); mHolder = this.getHolder(); mHolder.addCallback(this); mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { Contants.LogI("surfaceChanged"); mParameters = mCameraDevices.getParameters(); if(mParameters != null) mParameters.setPictureFormat(PixelFormat.JPEG); mParameters.setPreviewSize(320, 480); mParameters.setPictureSize(320, 480); mCameraDevices.setParameters(mParameters); mCameraDevices.startPreview(); } @Override public void surfaceCreated(SurfaceHolder holder) { Contants.LogI("surfaceCreated"); try { mCameraDevices = Camera.open(); mCameraDevices.setPreviewDisplay(mHolder); } catch (Exception e) { if(mCameraDevices != null) mCameraDevices.release(); mCameraDevices = null; } } @Override public void surfaceDestroyed(SurfaceHolder holder) { Contants.LogI("surfaceDestroyed"); if(mCameraDevices == null) return; mCameraDevices.stopPreview(); mCameraDevices.release(); mCameraDevices = null; } /** * 设置手电筒的开关状态 * @param on : true则打开,false则关闭 */ public void setFlashlightSwitch(boolean on){ if(mCameraDevices == null) return; if(mParameters == null){ mParameters = mCameraDevices.getParameters(); } if(on){ mParameters.setFlashMode(Contants.FLASH_MODE_TORCH); }else{ mParameters.setFlashMode(Contants.FLASH_MODE_OFF); } Contants.LogI("setFlashlightSwitch-----------------" + on); mCameraDevices.setParameters(mParameters); } }
布局文件main.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <com.android.flashlight.FlashlightSurface android:id="@+id/surfaceview" android:layout_width="fill_parent" android:layout_height="fill_parent" ></com.android.flashlight.FlashlightSurface> <ImageView android:id="@+id/image" android:layout_width="fill_parent" android:layout_height="fill_parent" android:src="@drawable/flashlight_off" android:background="#FFFFFFFF" /> </RelativeLayout>
显然这里打开了一个预览,可是被图片盖上了,看不见而已。不然闪光灯不亮。
这里有个Demo:http://download.csdn.net/detail/liu_zhen_wei/4801779
包含widget窗体小部件的使用方法和手电筒的功能实现,安装后,加入�窗体小部件(手电筒)到桌面,然后点击小部件后,打开手电筒的界面
点击界面,实现 打开/关闭 手电筒。