Question

我为AsyncTask创建了一个新文件，因此我可以将我的代码分解为MVP。

文件： TranslateAddress.java

public class TranslateAddress extends AsyncTask<String, Void, String> {

final Dialog customDialog = new Dialog(MainActivity.this); 

protected void onPreExecute() {
    super.onPreExecute();
    customDialog.setContentView(R.layout.custom_location_dialog);
    customDialog.setTitle("Looking for address");
    TextView text = (TextView) customDialog.findViewById(R.id.textView);
    text.setText("Looking for address");
    customDialog.show();

}

protected String doInBackground(String... params) {

    Geocoder geocoder;
    List<Address> addresses = null;
    geocoder = new Geocoder(MainActivity.this, Locale.getDefault());
    if (geocoder != null) {
        try {
            addresses = geocoder.getFromLocation(latitude, longitude, 1); // Here 1 represent max location result to returned, by documents it recommended 1 to 5
        } catch (IOException e) {
            e.printStackTrace();
        }
        address = addresses.get(0).getAddressLine(0); // If any additional address line present than only, check with max available address lines by getMaxAddressLineIndex()
        city = addresses.get(0).getLocality();
        state = addresses.get(0).getAdminArea();
        country = addresses.get(0).getCountryName();
        postalCode = addresses.get(0).getPostalCode();
        knownName = addresses.get(0).getFeatureName(); // Only if available else return NULL
        // do download here
    } else {
        Log.e("Error", "Geocoder returned Null");
        MainActivity.OpenFragment("SolicitationFramgnet");
    }
    return null;
}

protected void onPostExecute(String result) {
    super.onPostExecute(result);
    //dialog.dismiss();
    customDialog.dismiss();
    EditText localText = (EditText) findViewById(R.id.localText);
    if (localText != null) {
        localText.setText(address);
    }
}
}

这些是有错误的行：

final Dialog customDialog = new Dialog(MainActivity.this);

错误： MainActivity不是封闭类

geocoder = new Geocoder(MainActivity.this, Locale.getDefault());

错误：与上述相同，MainActivity不是封闭类

MainActivity.OpenFragment("SolicitationFramgnet");

错误：非静态方法无法从静态上下文引用OpenFragment。 我可以通过使OpenFragment静态修复此错误，但是，它会破坏其中一半的代码。

EditText localText = (EditText) findViewById(R.id.localText);

错误：无法解析方法“findViewById（int）”

Answer 1

将您的AsyncTask移动到另一个.java文件，您将丢失MainActivity的引用，因为在它作为InnerClass运行之前它现在只是一个Java类，因此您无法使用MainActivity这种情况下的方法或静态上下文。对findViewById方法来说是一回事，因为它属于您的Activity，而不属于您的AsyncTask。要修复它，您必须在构造函数和主布局中传递上下文，以便您可以使用此视图（作为构造函数的参数）在FindViewById文件中使用TranslateAddress方法。

这样的事情：

public class TranslateAddress extends AsyncTask<String, Void, String> {

final Dialog customDialog;
private MainActivity mainActivity;
private View view;

public TranslateAddress(View view, MainActivity mainActivity){
    this.view = view;
    this.mainActivity = mainActivity;
}



protected void onPreExecute() {
    super.onPreExecute();

    customDialog = new Dialog(mainActivity); 
    customDialog.setContentView(R.layout.custom_location_dialog);
    customDialog.setTitle("Looking for address");
    TextView text = (TextView) customDialog.findViewById(R.id.textView);
    text.setText("Looking for address");
    customDialog.show();

}

protected String doInBackground(String... params) {

    Geocoder geocoder;
    List<Address> addresses = null;
    geocoder = new Geocoder(mainActivity, Locale.getDefault());
    if (geocoder != null) {
        try {
            addresses = geocoder.getFromLocation(latitude, longitude, 1); // Here 1 represent max location result to returned, by documents it recommended 1 to 5
        } catch (IOException e) {
            e.printStackTrace();
        }
        address = addresses.get(0).getAddressLine(0); // If any additional address line present than only, check with max available address lines by getMaxAddressLineIndex()
        city = addresses.get(0).getLocality();
        state = addresses.get(0).getAdminArea();
        country = addresses.get(0).getCountryName();
        postalCode = addresses.get(0).getPostalCode();
        knownName = addresses.get(0).getFeatureName(); // Only if available else return NULL
        // do download here
    } else {
        Log.e("Error", "Geocoder returned Null");
       mainActivity.OpenFragment("SolicitationFramgnet");
    }
    return null;
}

protected void onPostExecute(String result) {
    super.onPostExecute(result);
    //dialog.dismiss();
    customDialog.dismiss();
    EditText localText = (EditText) view.findViewById(R.id.localText);
    if (localText != null) {
        localText.setText(address);
    }
}
}

Answer 2

对于上下文，请从MainActivity传递它，如下所示：

在AsyncTask中，创建一个构造函数

Context context;
TranslateAddress(Context c){
    context = c;
}

现在使用context代替MainActivity.this。并从MainActivity执行AsyncTask，如下所示：

new TranslateAddress(this).execute();

和findViewById()，请使用以下代码：

context.findViewById("YOUR_ID");

将AsyncTask移动到新文件

2 个答案: