无法显示我的自定义SurfaceView的2个实例

Question

我已经创建了自己的自定义SurfaceView,它可以自行运行,但是当我尝试将两个放在TabWidget中的单独选项卡上时,无论选择哪个选项卡,都会显示一个,并且它总是首先绘制的SurfaceView应用开始.

为了说明问题,我创建了可以编译显示问题的示例代码.

下面的SurfaceView(称为SurfaceViewCircle)只是创建一个位图,默认情况下绘制一个蓝色圆圈然后显示它.有一个公共方法,changeColour(),它将改变位图中的圆形颜色.

其次,我创建了一个XML布局,它只包含一个SurfaceViewCircle实例.

在Activity类中,我创建了一个TabWidget和主机等.然后我将上面的XML充气两次,但在一个实例中,我将SurfaceViewCircle的颜色更改为红色.一旦应用程序运行,无论我选择哪个选项卡,当应用程序退出并显示蓝色圆圈时,红色圆圈始终显示为例外情况.

有人能指出我在使用SurfaceView时错过了一个步骤吗？

这是活动代码:

public class TestActivity extends Activity  {
/** Called when the activity is first created. */

private TabHost mTabHost;
private Context mTabHostContext;
private View surfaceView1, surfaceView2;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    /*
     * Setup tabs
     */
    setContentView(R.layout.maintabs);
        setupTabHost(); //Prepares the TabHost from code rather than XML;
    mTabHost.getTabWidget().setDividerDrawable(R.drawable.tab_divider); //Sets a thin dividing line
    mTabHostContext = mTabHost.getContext();
    surfaceView1 = LayoutInflater.from(mTabHostContext).inflate(R.layout.surfaceviewindependent, null);
    SurfaceViewCircle s = (SurfaceViewCircle)surfaceView1.findViewById(R.id.circle1);
    /*
     * Change the colour to red
     */
    s.changeColour(getResources().getColor(R.color.red_square));

    /*
     * Create a second layout containing SurfaceViewCircle but leave circle as default blue.
     */
    surfaceView2 = LayoutInflater.from(mTabHostContext).inflate(R.layout.surfaceviewindependent, null);
    setupTab(surfaceView1,"SurfaceView1");
    setupTab(surfaceView2,"SurfaceView2");


}

private void setupTabHost() {
    mTabHost = (TabHost) findViewById(android.R.id.tabhost);
    mTabHost.setup();
}

private void setupTab(final View view, final String tag) {
    View tabview = createTabView(mTabHost.getContext(), tag); // This creates a view to be used in the TAB only

    /* this creates the tab content AND applies the TAB created in the previous step in one go */
    TabSpec setContent = mTabHost.newTabSpec(tag).setIndicator(tabview).setContent(new TabContentFactory() {
        public View createTabContent(String tag) {return view;}
    });
    mTabHost.addTab(setContent);

}

private static View createTabView(final Context context, final String text) {
    View view = LayoutInflater.from(context).inflate(R.layout.tabs_bg, null);
    TextView tv = (TextView) view.findViewById(R.id.tabsText);
    tv.setText(text);

    return view;
}   
}

这是我的自定义SurfaceView:

public class SurfaceViewCircle extends SurfaceView implements SurfaceHolder.Callback{

private Paint paint, circlePaint;
private Bitmap bitmap = null;
private int w;
private int h;
private int colour = 0;
private Resources r = null;
private _Thread t = null;
private boolean surfaceIsCreated;

public SurfaceViewCircle(Context context) {
    super(context);
    initialise();
}

public SurfaceViewCircle(Context context, AttributeSet attrs) {
    super(context, attrs);
    initialise();
}

public SurfaceViewCircle(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    initialise();
}

private void initialise(){
    r = getResources();
    getHolder().addCallback(this);
    paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    paint.setFilterBitmap(true);
    colour = R.color.blue_square;
    circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    circlePaint.setColor(r.getColor(colour));
    circlePaint.setStyle(Style.FILL);
    circlePaint.setStrokeWidth(0.02f);
    t = new _Thread(getHolder());


}

public void changeColour(int colour){
    circlePaint.setColor(colour);
    if (surfaceIsCreated){
        createBitmap();
    }
    synchronized (t){
        t.notify();
    }
}

private Bitmap createBitmap(){
    Bitmap b = null;
    b = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(b);
    c.scale((float)w, (float)w);        //Scales the background for whatever pixel size
    c.drawCircle(0.5f, 0.5f, 0.5f, circlePaint);
    //c.drawColor(r.getColor(colour));
    return b;
}

public void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
    int width = measure(widthMeasureSpec);
    int height = measure(heightMeasureSpec);

    int d = Math.min(width, height);
    setMeasuredDimension(d,d);
}

private int measure(int measureSpec) {
    int result = 0;
    // Decode the measurement specifications
    int specMode = MeasureSpec.getMode(measureSpec);
    int specSize = MeasureSpec.getSize(measureSpec);

    return specSize;
}

@Override
protected void onSizeChanged(int w, int h, int oldW, int oldH){
    super.onSizeChanged(w, h, oldW, oldH);
    //synchronized (this){
        this.w = Math.min(w, h);
        this.h = w;
    //}
    Bitmap b = createBitmap();

        bitmap = b;

    Log.i("Square", "onSizeChanged() called.");


}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    // TODO Auto-generated method stub

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    Log.i("Panel", "surfaceCreated() called.");
    t.setRunning(true);
    t.start();
    surfaceIsCreated = true;

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    Log.i("Square", "surfaceDestroyed() called.");

    surfaceIsCreated = false;
    boolean retry = true;
    synchronized (t){
        t.setRunning(false);
        t.notify();
    }
    while (retry) {
        try {
            t.join();
            retry = false;
        } catch (InterruptedException e) {
            // we will try it again and again...
        }
    }

}

private class _Thread extends Thread {
    private SurfaceHolder _surfaceHolder;
    private boolean _run = false;

    public _Thread(SurfaceHolder surfaceHolder) {
        _surfaceHolder = surfaceHolder;
    }

    public void setRunning(boolean run) {
        _run = run;
    }

    @Override
    public void run() {
        Canvas c = null;
        while (_run){
            try {
                c = _surfaceHolder.lockCanvas(null);
                synchronized (_surfaceHolder) {
                    synchronized(bitmap){
                        c.drawBitmap(bitmap, 0, 0, paint);
                    }
                }
            } finally {
                // do this in a finally so that if an exception is thrown
                // during the above, we don't leave the Surface in an
                // inconsistent state
                if (c != null) {
                    _surfaceHolder.unlockCanvasAndPost(c);
                }
            }
            synchronized(this){
                try {
                    wait();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block

                }
            }
        }
    }
}
}

maintabs.xml文件:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/tabhost" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout android:orientation="vertical"
        android:layout_width="fill_parent" android:layout_height="fill_parent">
        <TabWidget android:id="@android:id/tabs"
            android:layout_width="fill_parent" android:layout_height="wrap_content"
            android:layout_marginLeft="0dip" android:layout_marginRight="0dip" />
            <FrameLayout android:id="@android:id/tabcontent"
            android:layout_width="fill_parent" android:layout_height="fill_parent" />
    </LinearLayout>
    </TabHost>
</LinearLayout>

和surfaceviewindependent.xml:

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
<uk.co.androidcontrols.gauges.SurfaceViewCircle
android:id="@+id/circle1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="0.5"
    android:layout_margin="1dip">
</uk.co.androidcontrols.gauges.SurfaceViewCircle>
</LinearLayout>

我还注意到其他人在这里遇到过类似的问题.

抱歉格式不佳,但代码编辑器几乎不可能用于大型代码报价!

附加信息

我尝试使用setVisibility()'in onvisibilityChanged()但它最终导致异常:

protected void onVisibilityChanged(View changedView, int visibility){
    super.onVisibilityChanged(changedView, visibility);
    changedView.setVisibility(visibility);
    Log.i("SurfaceViewCircle", "onVisibilityChanged() called.");
}

java.lang.IllegalThreadStateException: Thread already started.

它似乎changedView.setvisibility()每次都会破坏表面.

Answer 1

看起来我想用 SurfaceView 做的事情不推荐：链接