AsyncTask不通用？

Question

当我尝试编译为以下代码时,我得到两个错误:

说明资源路径位置类型令牌"void"上的语法错误,无效表达式AsyncTask.java /AsyncTask Project/src/org/me/asynctask行19 Java问题

说明资源路径位置类型类型AsyncTask不是通用的; 它不能用参数<TextView, Void, Void> AsyncTask.java /AsyncTask Project/src/org/me/asynctask第25行Java问题进行参数化

package org.me.asynctask;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;
import android.os.*;
public class AsyncTask extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        TextView mytextview = new TextView(this);
        TextView secondtextview = new TextView(this);

        new MyAsyncClass().execute(mytextview, void, secondtextview);
    }

    private class MyAsyncClass extends AsyncTask<TextView, Void, Void> {
    protected TextView doInBackground(TextView tv)
    {
        tv.setText("Your AsyncTask was successful!");
        return tv;
    }

    protected void onPostExecute(TextView Result)
    {
        Context context = context.getApplicationContext();
        Toast mytoast = Toast.makeText(context, "AsyncTask processing complete", Toast.LENGTH_LONG);
        mytoast.show();
    }
}

显然AsyncTask是一个通用的(http://developer.android.com/reference/android/os/AsyncTask.html#execute(Params ...) 所以为什么我会得到这些错误？

Answer 1

您使用错误的类型覆盖AsyncTask方法.它被定义为:

AsyncTask<Params, Progress, Result>

并且doInBackground方法被定义为受保护的抽象结果doInBackground(Params ... params)

所以根据你的定义,你应该保护Void doInBackround(TextView ... params);

onPostExecute也未正确定义.