java - 如何将上下文传递给 AsyncTask？

Question

如何在 Async Task 类中传递上下文，该类是在 Main Activity 不同的 java 文件中编码的，但它是从 main Activity 调用的？

下面是我的代码:

 @Override

protected void onPostExecute(List<Movie_ModelClass> result) {
        super.onPostExecute(result);

        if (result != null) {
            Movie_Adapter movieAdapter = new Movie_Adapter(new MainActivity().getApplicationContext() , R.layout.custom_row, result);
            MainActivity ovj_main = new MainActivity();
            ovj_main.lv_main.setAdapter(movieAdapter);
        } else {
            Toast.makeText(new MainActivity().getApplicationContext() ,"No Data Found", Toast.LENGTH_LONG);

        }
        if (progressDialog.isShowing()) {
            progressDialog.dismiss();
    }

Answer 1

您可以将 Context 实例作为构造函数参数传递(并为其保留 WeakReference 以避免内存泄漏)。

例如:

public class ExampleAsyncTask extends AsyncTask {
    private WeakReference<Context> contextRef;

    public ExampleAsyncTask(Context context) {
        contextRef = new WeakReference<>(context);
    }

    @Override
    protected Object doInBackground(Object[] params) {
        // ...
    }

    @Override
    protected void onPostExecute(Object result) {
        Context context = contextRef.get();
        if (context != null) {
            // do whatever you'd like with context
        }
    }
}

以及执行:

new ExampleAsyncTask(aContextInstance).execute();