Question

我想在显示器上画一条线（相机预览）。我想在相机屏幕上显示相机时画一条线（就像油漆一样）。

Answer 1

您可以使用类似下图的布局：

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.example.YourTextureViewForCameraDisplay
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <com.example.YourOverlayLayout - your overlay where your draw a line, or a regular layout (like a FrameLayout) where you put a drawable with a line
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerInParent="true" />

</RelativeLayout>

Answer 2

以下代码段会帮助您。

public class SurfaceViewLineDemo extends Activity implements SurfaceHolder.Callback {

private static final String TAG = "TestSurface";

/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    SurfaceView view = new SurfaceView(this);
    setContentView(view);
    view.getHolder().addCallback(this);
} 

@Override 
public void surfaceCreated(SurfaceHolder holder) {
    tryDrawing(holder);
} 

@Override 
public void surfaceChanged(SurfaceHolder holder, int frmt, int w, int h) { 
    tryDrawing(holder);
} 

@Override 
public void surfaceDestroyed(SurfaceHolder holder) {}

private void tryDrawing(SurfaceHolder holder) {
    Log.i(TAG, "Trying to draw...");

    Canvas canvas = holder.lockCanvas();
    if (canvas == null) {
        Log.e(TAG, "Cannot draw onto the canvas as it's null");
    } else { 
        drawMyStuff(canvas);
        holder.unlockCanvasAndPost(canvas);
    } 
} 

private void drawMyStuff(final Canvas canvas) {
    Random random = new Random();
    Log.i(TAG, "Drawing...");
    canvas.drawRGB(255, 128, 128);
} }

我想在显示器上画一条线（相机预览）

2 个答案: