Question

我有一个问题：我想方法exprrasionCalculatePoints在一个胎面计算，当它计算时，必须有进度条显示进度。当计算点数时，我绘制一个图表。但是有两个问题，当我按下屏幕而不是计算点数时，进度条停止第二个问题是：

graph = new GraphPanel(getApplicationContext());
setContentView(graph);

这两行必须在一个metod计算全部之前执行。我该如何解决这两个问题？

源代码：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        final ProgressDialog ringProgressDialog = ProgressDialog.show(this,
                "Please wait ...", "Downloading Image ...", true);

        setContentView(R.layout.drawsurface);
        ringProgressDialog.setCancelable(true);

        new Thread(new Runnable() {

            @Override
            public void run() {

                try {

                    Calculator.expr[0].exprasionCalculatePoints();
                } catch (Exception e) {
                    Log.e(e.getMessage(), e.getMessage());

                }

                ringProgressDialog.dismiss();

                graph = new GraphPanel(getApplicationContext());
                setContentView(graph);

            }
        }).start();

    }

}

logcat的

  08-11 04:56:37.253: E/AndroidRuntime(2681): FATAL EXCEPTION: Thread-149
08-11 04:56:37.253: E/AndroidRuntime(2681): Process: com.example.mycalc, PID: 2681
08-11 04:56:37.253: E/AndroidRuntime(2681): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
08-11 04:56:37.253: E/AndroidRuntime(2681):     at android.os.Handler.<init>(Handler.java:200)
08-11 04:56:37.253: E/AndroidRuntime(2681):     at android.os.Handler.<init>(Handler.java:114)
08-11 04:56:37.253: E/AndroidRuntime(2681):     at android.view.SurfaceView$1.<init>(SurfaceView.java:118)
08-11 04:56:37.253: E/AndroidRuntime(2681):     at android.view.SurfaceView.<init>(SurfaceView.java:118)
08-11 04:56:37.253: E/AndroidRuntime(2681):     at com.calculator.grap.GraphPanel.<init>(GraphPanel.java:31)
08-11 04:56:37.253: E/AndroidRuntime(2681):     at com.calculator.grap.GraphingTab$1.run(GraphingTab.java:58)
08-11 04:56:37.253: E/AndroidRuntime(2681):     at java.lang.Thread.run(Thread.java:841)

Answer 1

您需要在UI线程上运行它们。尝试这样的事情：

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

    final ProgressDialog ringProgressDialog = ProgressDialog.show(this,
            "Please wait ...", "Downloading Image ...", true);

    setContentView(R.layout.drawsurface);
    ringProgressDialog.setCancelable(true);

    new Thread(new Runnable() {

        @Override
        public void run() {

            try {

                Calculator.expr[0].exprasionCalculatePoints();
            } catch (Exception e) {
                Log.e(e.getMessage(), e.getMessage());

            }

            runOnUiThread(display);


        }
    }).start();

}

Runnable display = new Runnable() {
    @Override
    public void run () {
            ringProgressDialog.dismiss();

            graph = new GraphPanel(getApplicationContext());
            setContentView(graph);
    }
}

Answer 2

progressBar是一个UI组件。你不能在一个线程内调用它。尝试使用runOnUiThread

线程：无法在未调用的线程内创建处理程序

2 个答案: