java - 使用 ProgressDialog 和 Threads 时应用程序崩溃

Question

这是我第一次使用 ProgressDialog 和 Threads。当我尝试使用 ProgressDialog 应用程序崩溃时。

ProgressDialog 和线程代码:

 pd = ProgressDialog.show(MainScreen.this, "Backup", "Please, wait...", true, true);
     final Handler handler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                    pd.dismiss();

            }
    };
    new Thread (new Runnable() { 
         public void run() {
             Looper.prepare();
                DB = new DataBase(MainScreen.this);
                Cursor r = DB.fetchAllNames();
                if (r.getCount() == 0){
                    File sdPath = Environment.getExternalStorageDirectory();
                    File sdPathDr = new File(sdPath.getAbsolutePath() + "/Pass_backup/" + DIR_SD);
                    if(!sdPathDr.exists()){
                    }
                    else {
                        File[] files = sdPathDr.listFiles();
                        if (files.length == 0){
                        }
                        else {
                            try {
                                restoring();
                            } catch (IOException e2) {
                                e2.printStackTrace();
                            }
                        }
                 }
             }   
             else {
                try {
                    backupAdapter();
                } catch (IOException e1) {
                    e1.printStackTrace();
                } 
                try {
                    restoring();
                } catch (IOException e) {
                    e.printStackTrace();
                    }
             }
                handler.sendEmptyMessage(0);
            }}).start(); 

线程内的代码可以工作，但应用程序崩溃。

日志猫:

03-29 15:49:06.754: E/AndroidRuntime(12608): FATAL EXCEPTION: Thread-8781
03-29 15:49:06.754: E/AndroidRuntime(12608): Process: com.ssd.passwordbook, PID: 12608
03-29 15:49:06.754: E/AndroidRuntime(12608):android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6094)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:857)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.ViewGroup.invalidateChild(ViewGroup.java:4320)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.View.invalidate(View.java:10942)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.View.invalidate(View.java:10897)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.widget.ImageView.invalidateDrawable(ImageView.java:201)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.graphics.drawable.Drawable.invalidateSelf(Drawable.java:344)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.graphics.drawable.Drawable.setVisible(Drawable.java:575)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.widget.ImageView.onDetachedFromWindow(ImageView.java:1243)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.View.dispatchDetachedFromWindow(View.java:12627)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2585)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.view.ViewGroup.removeAllViewsInLayout(ViewGroup.java:4027)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.widget.AbsListView.resetList(AbsListView.java:1924)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.widget.ListView.resetList(ListView.java:521)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at android.widget.ListView.setAdapter(ListView.java:462)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at com.ssd.passwordbook.MainScreen.loaderAdapter(MainScreen.java:930)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at com.ssd.passwordbook.MainScreen.restoring(MainScreen.java:1068)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at com.ssd.passwordbook.MainScreen$9.run(MainScreen.java:728)
03-29 15:49:06.754: E/AndroidRuntime(12608):    at java.lang.Thread.run(Thread.java:841)

那么，我该如何解决这个问题呢？

Answer 1

您是否在线程内进行 ui 工作。如果是，请使用 using 进行 UI 工作

runOnUiThread(new Runnable() {
    public void run() {
       //UI Works
    }
});