6
我正在寫一個Android相機應用程序，並試圖實現Flash功能，我使用SurfaceView，每當我點擊閃光按鈕切換作品，但閃光燈沒有來...看到我的下面的代碼我已經習慣打開/關閉手電筒。打開/關閉使用SurfaceView的手電筒
完整代碼： -
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
preview=(SurfaceView)findViewById(R.id.surface);
previewHolder=preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
previewHolder.setFixedSize(getWindow().getWindowManager()
.getDefaultDisplay().getWidth(), getWindow().getWindowManager()
.getDefaultDisplay().getHeight());
btnFlash = (ImageButton) findViewById(R.id.btnFlash);
/*
* First check if device is supporting flashlight or not
*/
hasFlash = getApplicationContext().getPackageManager()
.hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
if (!hasFlash) {
// device doesn't support flash
// Show alert message and close the application
AlertDialog alert = new AlertDialog.Builder(CameraLauncherActivity.this)
.create();
alert.setTitle("Error");
alert.setMessage("Sorry, your device doesn't support flash light!");
alert.setButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// closing the application
finish();
}
});
alert.show();
return;
}
// displaying button image
toggleButtonImage();
btnFlash.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (isFlashOn) {
// turn off flash
turnOffFlash();
} else {
// turn on flash
turnOnFlash();
}
}
});
}
/*
* Turning On flash
*/
private void turnOnFlash() {
if (!isFlashOn) {
if (camera == null || params == null) {
return;
}
params = camera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_ON);
camera.setParameters(params);
isFlashOn = true;
// changing button/switch image
toggleButtonImage();
}
}
/*
* Turning Off flash
*/
private void turnOffFlash() {
if (isFlashOn) {
if (camera == null || params == null) {
return;
}
params = camera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(params);
isFlashOn = false;
// changing button/switch image
toggleButtonImage();
}
}
/*
* Toggle switch button images
* changing image states to on/off
* */
private void toggleButtonImage(){
if(isFlashOn){
btnFlash.setImageResource(R.drawable.green_button);
}else{
btnFlash.setImageResource(R.drawable.red_button);
}
}
@Override
public void onResume() {
super.onResume();
camera=Camera.open();
}
@Override
public void onPause() {
super.onPause();
if (inPreview) {
camera.stopPreview(); }
camera.release();
camera=null;
inPreview=false;
}
private Camera.Size getBestPreviewSize(int width, int height,Camera.Parameters parameters){
Camera.Size result=null;
for (Camera.Size size : parameters.getSupportedPreviewSizes())
{
if (size.width<=width && size.height<=height)
{
if (result==null) {
result=size;
} else {
int resultArea=result.width*result.height;
int newArea=size.width*size.height;
if (newArea>resultArea) {
result=size;
}
}
}
}
return(result);
}
SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback(){
public void surfaceCreated(SurfaceHolder holder) {
try {
camera.setPreviewDisplay(previewHolder);
} catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback",
"Exception in setPreviewDisplay()", t);
Toast.makeText(CameraLauncherActivity.this, t.getMessage(), Toast.LENGTH_LONG).show();
}
}
public void surfaceChanged(SurfaceHolder holder,int format, int width,int height) {
params = camera.getParameters();
params.setFlashMode(Camera.Parameters.FLASH_MODE_ON);
Camera.Size size=getBestPreviewSize(width, height,
params);
if (size!=null) {
params.setPreviewSize(size.width, size.height);
camera.setParameters(params);
camera.startPreview();
inPreview=true;
ZoomControls zoomControls = (ZoomControls) findViewById(R.id.zoomControls);
if (params.isZoomSupported()) {
final int maxZoomLevel = params.getMaxZoom();
Log.i("max ZOOM ", "is " + maxZoomLevel);
zoomControls.setIsZoomInEnabled(true);
zoomControls.setIsZoomOutEnabled(true);
zoomControls.setOnZoomInClickListener(new OnClickListener(){
public void onClick(View v){
if(currentZoomLevel < maxZoomLevel){
currentZoomLevel++;
//mCamera.startSmoothZoom(currentZoomLevel);
params.setZoom(currentZoomLevel);
camera.setParameters(params);
}
}
});
zoomControls.setOnZoomOutClickListener(new OnClickListener(){
public void onClick(View v){
if(currentZoomLevel > 0){
currentZoomLevel--;
params.setZoom(currentZoomLevel);
camera.setParameters(params);
}
}
});
}
else
zoomControls.setVisibility(View.GONE);
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
}
};
}
您的設備可能有多個攝像頭（例如背面朝前），但並非全部都有閃光燈。迭代所有相機，直到你找到一個支持閃光燈，並打開相機 – yoah
@yoah我使用的是Galaxy EK-GC100相機，它只有後置相機 – Sun