Android 开启闪光灯做手电筒

public class HandLightActivity extends Activity implements OnClickListener{


private ToggleButton toggleButton;
private Camera m_Camera;

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.handlight);

toggleButton = (ToggleButton)this.findViewById(R.id.toggleButton1);
toggleButton.setOnClickListener(this);

getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
}

@Override
public void onClick(View v) {
ToggleButton tb = (ToggleButton)v;
if(!tb.isChecked()){
PackageManager pm= this.getPackageManager();
FeatureInfo[] features=pm.getSystemAvailableFeatures();
for(FeatureInfo f : features)
{
if(PackageManager.FEATURE_CAMERA_FLASH.equals(f.name)) //判断设备是否支持闪光灯
{
if ( null == m_Camera )
{
m_Camera = Camera.open();
}

Camera.Parameters parameters = m_Camera.getParameters();
parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
m_Camera.setParameters( parameters );
m_Camera.startPreview();
toggleButton.setBackgroundColor(0x30ffffff);
}
}
}else{
if ( m_Camera != null )
{
m_Camera.stopPreview();
m_Camera.release();
m_Camera = null;
}
toggleButton.setBackgroundColor(0xffffffff);
}
}
}

handlight.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ToggleButton android:id="@+id/toggleButton1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:checked="true"
android:text="ToggleButton"/>
</LinearLayout>

需要加上权限

<uses-permission android:name="android.permission.FLASHLIGHT"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.hardware.camera"/>

注意：并不是所有的设备都支持

网上还有一种说法是调用系统隐藏api，不过我试了没反应，可能是系统版本问题，备份一下

用IHardwareService直接控制

Android1.5以前是直接提供这个接口的，之后呢，需要我们自己来做一下。

在你的项目中新建一个包Android.os,新建一个IHardwareService.aidl文件，内容如下：

1. packageandroid.os;
3. /**{@hide}*/
4. interfaceIHardwareService
5. {
6. //obsoleteflashlightsupport
7. booleangetFlashlightEnabled();
8. voidsetFlashlightEnabled(booleanon);
9. }

然后在你的程序中引入

importandroid.os.IHardwareService;

/**
*设置闪光灯的开启和关闭
*@paramisEnable
*@authorlinc
*@date2012-3-18
*/
privatevoidsetFlashlightEnabled(booleanisEnable)
{
try
{
Methodmethod=Class.forName("android.os.ServiceManager").getMethod("getService",String.class);
IBinderbinder=(IBinder)method.invoke(null,newObject[]{"hardware"});

IHardwareServicelocalhardwareservice=IHardwareService.Stub.asInterface(binder);
localhardwareservice.setFlashlightEnabled(isEnable);
}
catch(Exceptione)
{
e.printStackTrace();
}

}

这样就可以开启闪光灯了。要使用的权限：

1. <uses-permissionandroid:name="android.permission.FLASHLIGHT"/>
2. <uses-permissionandroid:name="android.permission.HARDWARE_TEST"/>