一、預覽 Camera 數據
做過Android開發的人一般都知道,有兩種方法能夠做到這一點:SurfaceView、TextureView。
下面是使用SurfaceView預覽數據的方式:
public class CameraTextureViewActivity extends AppCompatActivity implements SurfaceHolder.Callback {
private Camera camera;
private SurfaceView surfaceView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera_texture_view);
surfaceView = findViewById(R.id.surfaceView);
surfaceView.getHolder().addCallback(this);
// 打開攝像頭並將展示方向旋轉90度
camera = Camera.open();
camera.setDisplayOrientation(90);
}
//------ Surface 預覽 -------
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
camera.setPreviewDisplay(holder);
camera.startPreview();
} catch (IOException e) {
e.printStackTrace();
}
}
//窗口改變
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
camera.release();
}
}
使用TextureView預覽數據的方式:
public class CameraTextureViewActivity extends AppCompatActivity implements TextureView.SurfaceTextureListener {
private TextureView textureView;
private Camera camera;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera_texture_view);
textureView = findViewById(R.id.textureView);
textureView.setSurfaceTextureListener(this);
// 打開攝像頭並將展示方向旋轉90度
camera = Camera.open();
camera.setDisplayOrientation(90);
}
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
try {
camera.setPreviewTexture(surface);
camera.startPreview();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
camera.release();
return false;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surface) {
}
}
二、取到 NV21 的數據回調
Android 中Google支持的 Camera Preview Callback的YUV常用格式有兩種:一個是NV21,一個是YV12。Android一般默認使用YCbCr_420_SP的格式(NV21)。
我們可以配置數據回調的格式:
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewFormat(ImageFormat.NV21);
camera.setParameters(parameters);
通過setPreviewCallback方法監聽預覽的回調:
camera.setPreviewCallback(new Camera.PreviewCallback() {
@Override
public void onPreviewFrame(byte[] bytes, Camera camera) {
}
});
一定要加權限:
<uses-permission android:name="android.permission.CAMERA"/>