java - 为什么我不能在我的 Activity 中启动线程 2x？

Question

我将 Activity 中的 Web 服务调用推送到线程(如下所示)。我第一次在 Activity 中这样做时它工作正常(从我的编辑文本中获取文本并加载服务以获取纬度/经度数据)

但是当我单击后退按钮(模拟器)并尝试第二次触发该线程时，它在 .start(); 之后爆炸了。在我的点击处理程序中。我在这里做错了什么？谢谢

private Thread getLocationByZip = new Thread() {
    public void run() {
        try {
            EditText filterText = (EditText) findViewById(R.id.zipcode);
            Editable zip = filterText.getText();

            LocationLookupService locationLookupService = new LocationLookupService();
            selectedLocation = locationLookupService.getLocationByZip(zip.toString());

            locationHandler.post(launchFindWithLocationInfo);
        } catch (Exception e) {
        }
    }
};

private Runnable launchFindWithLocationInfo = new Runnable() {
    @Override
    public void run() {
        try {
            Intent abc = new Intent(LocationLookup.this, FindWithLocation.class);
            startActivity(abc);
        } catch (Exception e) {

        }
    }
};

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.location);

    locationHandler = new Handler();
    findViewById(R.id.findbyzip).setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View view) {
            getLocationByZip.start();
        }
    });
}

更新

在听取了很好的建议后，我选择了 AsyncTask，所以如果有人发现这会继续下去，上面的线程/处理程序模型看起来像下面的异步任务

private class LocationLookupTask extends AsyncTask<String, Void, Location> {
    private ProgressDialog dialog;

    @Override
    protected void onPreExecute() {
        this.dialog = ProgressDialog.show(LocationLookup.this, "", "Loading...");
    }

    @Override
    protected Location doInBackground(String... zips) {
        Location selectedLocation = null;
        for (String zip : zips) {
            LocationLookupService locationLookupService = new LocationLookupService();
            selectedLocation = locationLookupService.getLocationByZip(zip);
        }
        return selectedLocation;
    }

    @Override
    protected void onPostExecute(Location location) {
        this.dialog.dismiss();

        ((AppDelegate) getApplicationContext()).setSelectedLocation(location);
        Intent abc = new Intent(LocationLookup.this, FindWithLocation.class);
        startActivity(abc);
    }
}

现在要在 onclick 中调用它，您可以这样做

findViewById(R.id.findbyzip).setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                EditText filterText = (EditText) findViewById(R.id.zipcode);
                Editable zip = filterText.getText();

                LocationLookupTask task = new LocationLookupTask();
                task.execute(new String[]{zip.toString()});
            }
        });

Answer 1

你不能启动一个线程两次:

It is never legal to start a thread more than once.

取自Thread.start() .

因此，您需要创建一个新线程并启动该线程。