android - SurfaceHolder.lockCanvas() 太贵了

Question

每次我调用这些方法时，都需要 14-20 毫秒才能继续。

Canvas canvas = holder.lockCanvas();
holder.unlockCanvasAndPost(canvas);

这是正常行为吗？我应该采取不同的方法吗？

这是完整的代码

public class Render extends SurfaceView {
    Context c = null;
    SurfaceHolder holder;
    volatile boolean running = true;

    public Render(Context c) {
        super(c);
        this.c = c;
        this.holder = getHolder();
    }

    public void run() {
        if(running) { 
            if(!holder.getSurface().isValid()){
                System.out.println("not valid");
                return;          
            }

            Canvas canvas = holder.lockCanvas();
            holder.unlockCanvasAndPost(canvas);

        }
    }
}

追踪:

01-05 15:49:20.322: I/System.out(4892): Frame time: 0 ms frame291
01-05 15:49:20.322: I/System.out(4892): not valid
01-05 15:49:20.322: I/System.out(4892): Frame time: 0 ms frame292
01-05 15:49:20.332: I/System.out(4892): Frame time: 2 ms frame293
01-05 15:49:20.357: I/System.out(4892): Frame time: 22 ms frame294
01-05 15:49:20.357: I/System.out(4892): Frame time: 1 ms frame295
01-05 15:49:20.362: I/System.out(4892): Frame time: 1 ms frame296
01-05 15:49:20.367: D/CLIPBOARD(4892): Hide Clipboard dialog at Starting input: finished by someone else... !
01-05 15:49:20.367: I/System.out(4892): Frame time: 8 ms frame297
01-05 15:49:20.377: I/System.out(4892): Frame time: 10 ms frame298
01-05 15:49:20.397: I/System.out(4892): Frame time: 16 ms frame299
01-05 15:49:20.412: I/System.out(4892): Frame time: 16 ms frame300
01-05 15:49:20.427: I/System.out(4892): Frame time: 16 ms frame301

更新

---

当我使用 OpenGL 时发生同样的事情

package android.apps.td;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.opengl.GLSurfaceView.Renderer;

public class Render extends GLSurfaceView implements Renderer {

    private final int MILLION = 1000000;
    private long frame;

    public Render(Context context) {
        super(context);
        setRenderer(this);
        // TODO Auto-generated constructor stub
    }

    public void onDrawFrame(GL10 arg0) {
        System.out.println("Frame "+(System.nanoTime()-frame)/MILLION+" ms");
        frame = System.nanoTime();
    }

    public void onSurfaceChanged(GL10 gl, int width, int height) {
        System.out.println("Surface changed w:"+width+" h:"+height);
    }

    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
        System.out.println("Surface created");
    }
}

Answer 1

我发现了这篇文章:http://replicaisland.blogspot.com/2009/10/rendering-with-two-threads.html

eglSwapBuffers() 可能在 onDrawFrame 之后调用并阻塞，直到硬件完成绘制然后交换缓冲区，这需要 16.67 毫秒的最小延迟。