Android 處理圖像的方法 - (一) 避免記憶體不足的異常 - Android 台灣中文網

public class CameraRunActivity extends Activity implements Callback, OnClickListener {
private static final String TAG = CameraRunActivity.class.getSimpleName();
private SurfaceView surfaceview;
private SurfaceHolder surfaceholder;
private Camera myCamera;
private ImageView camera_action;
private Bitmap finalBMP;
private final int HANDLER_OF_PROCESS = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.camera_run);
setRequestedOrientation(1);
// 定義 Layout 中的 SurfaceView
surfaceview = (SurfaceView) findViewById(R.id.surfaceview);
surfaceholder = surfaceview.getHolder();
// 定義 SurfaceView Holder 相關的處理
surfaceholder.addCallback(this);
surfaceholder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
// 實際觸發拍照的物件
camera_action = (ImageView) findViewById(R.id.camera_action);
camera_action.setOnClickListener(this);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
Camera.Parameters parameters = myCamera.getParameters();
// 開啟自動對焦的模式
parameters.setFocusMode("auto");
// 設定輸出的圖像格式
parameters.setPictureFormat(PixelFormat.JPEG);
myCamera.setParameters(parameters);
// 同步 SurfaceView 與 Camera
myCamera.startPreview();
isCameraOpen = true;
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
myCamera = Camera.open();
myCamera.setPreviewDisplay(surfaceholder);
// 將相機轉 90 度，因為手機要保持直立
myCamera.setDisplayOrientation(90);
} catch (IOException e) {
myCamera.release();
myCamera = null;
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
myCamera.stopPreview();
isCameraOpen = false;
myCamera.release();
myCamera = null;
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.camera_action :
isCameraOpen = false;
// 先觸發自動對焦，然後再拍照
myCamera.autoFocus(autoFacusCallback);
break;
}
}
private ShutterCallback shutterCallback = new ShutterCallback() {
public void onShutter() {
// Shutter has closed
}
};
private PictureCallback rawCallback = new PictureCallback() {
public void onPictureTaken(byte[] _data, Camera _camera) {
// TODO Handle RAW image data
}
};
private PictureCallback jpegCallback = new PictureCallback() {
public void onPictureTaken(byte[] _data, Camera _camera) {
// 設定 inJustDecodeBounds = true
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
Bitmap bitmap_def = BitmapFactory.decodeByteArray(_data, 0, _data.length, options);
// 取得圖像的長寬
int width = bitmap_def.getWidth();
int height = bitmap_def.getHeight();
}
};
AutoFocusCallback autoFacusCallback = new AutoFocusCallback() {
@Override
public void onAutoFocus(boolean focused, Camera camera) {
// 當相機捉到焦點時，再啟動相機拍照
if (focused == true) {
myCamera.takePicture(shutterCallback, rawCallback, jpegCallback);
}
}
};
}

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