android手电筒原理很简单，就是打开相机的闪光灯。
核心的代码就这么多：
打开相机
设置闪光灯开
打开预览
设置相机的autoFocus
Camera camera = Camera.open();
Parameters mParameters = camera.getParameters();
mParameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
camera.setParameters(mParameters);
camera.startPreview();
camera.autoFocus(new AutoFocusCallback() {
public void onAutoFocus(boolean success, Camera camera) {
}
});
这几个步骤缺1不可。照网上之前的例子试了，1直不成功。就是由于有些缺了打开预览，有些缺了autoFocus
然后就是设置权限
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.FLASHLIGHT" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<uses-feature android:name="android.hardware.camera.flash" />
最后贴以下完全的Activity。我这个很简单，create的时候就打开手电筒，屏幕上显示”Flashlight open“，按返回键，关闭并退出利用。
package org.lhc.flashlight;
import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.widget.TextView;
public class MainActivity extends Activity {
private Camera camera = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.camera = Camera.open();
if (this.camera != null) {
Parameters mParameters = camera.getParameters();
mParameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
camera.setParameters(mParameters);
camera.startPreview();
camera.autoFocus(new AutoFocusCallback() {
public void onAutoFocus(boolean success, Camera camera) {
}
});
TextView info = (TextView)this.findViewById(R.id.flashlight_info);
info.setText("Flashlight open");
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
if (this.camera != null) {
Parameters mParameters = camera.getParameters();
mParameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
camera.setParameters(mParameters);
camera.stopPreview();
camera.release();
}
Log.i("Flashlight", "exit");
this.finish();
System.exit(0);
}
return super.onKeyDown(keyCode, event);
}
}
转载请注明出处
http://blog.csdn.net/redstarofsleep