Java 扩展ListActivity时类强制转换异常

我想知道为什么当我运行我的应用程序并尝试点击Daily Forecast选项时会出现以下日志

  Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.ListView

这是我的日常预测活动

package com.dredaydesigns.stormy.ui;

import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Parcelable;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;

import com.dredaydesigns.stormy.R;
import com.dredaydesigns.stormy.adapters.DayAdapter;
import com.dredaydesigns.stormy.weather.Day;

import java.util.Arrays;

public class DailyForecastActivity extends ListActivity {

    private Day[] mDays;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_daily_forecast);

        Intent intent = getIntent();
        Parcelable[] parcelables = intent.getParcelableArrayExtra(MainActivity.DAILY_FORECAST);
        mDays = Arrays.copyOf(parcelables, parcelables.length, Day[].class);
        DayAdapter adapter = new DayAdapter(this, mDays);

    }


    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);

        String dayOfTheWeek = mDays[position].getDayOfTheWeek();
        String conditions = mDays[position].getSummary();
        String highTemp = mDays[position].getTemperatureMax()  + "";
        String message = String.format("On %s the high will be %s and it will be %s", dayOfTheWeek, highTemp, conditions);
        Toast.makeText(this, message, Toast.LENGTH_LONG).show();
    }
}

编辑：对不起，忘了发布这个！这里是每日活动预测

'package com.dredaydesigns.stormy.ui;

import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Parcelable;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;

import com.dredaydesigns.stormy.R;
import com.dredaydesigns.stormy.adapters.DayAdapter;
import com.dredaydesigns.stormy.weather.Day;

import java.util.Arrays;

import butterknife.ButterKnife;

public class DailyForecastActivity extends ListActivity {

    private Day[] mDays;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_daily_forecast);
        ButterKnife.inject(this);
        Intent intent = getIntent();
        Parcelable[] parcelables = intent.getParcelableArrayExtra(MainActivity.DAILY_FORECAST);
        mDays = Arrays.copyOf(parcelables, parcelables.length, Day[].class);
        DayAdapter adapter = new DayAdapter(this, mDays);

    }


    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);

        String dayOfTheWeek = mDays[position].getDayOfTheWeek();
        String conditions = mDays[position].getSummary();
        String highTemp = mDays[position].getTemperatureMax()  + "";
        String message = String.format("On %s the high will be %s and it will be %s", dayOfTheWeek, highTemp, conditions);
        Toast.makeText(this, message, Toast.LENGTH_LONG).show();
    }
}
'

---

是否需要以不同的方式声明ListActivity？

将您的

ListView

id设置为

@android:id/list

，然后您的

onCreate

方法将被禁用

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_daily_forecast);

        Intent intent = getIntent();
        Parcelable[] parcelables = intent.getParcelableArrayExtra(MainActivity.DAILY_FORECAST);
        mDays = Arrays.copyOf(parcelables, parcelables.length, Day[].class);
        DayAdapter adapter = new DayAdapter(this, mDays);
        setListAdapter(adapter);
    }

---

您还需要发布您的

活动\每日\预测

。因此，我们至少可以试着看看有什么问题。请看类似的问题和答案：，我看了几个，但仍然无法得到它smhit当前设置为@android:id/list，但我确实尝试并实现了你的onCreate方法，并得到了这个错误，我相信是一样的。java.lang.ClassCastException:android.widget.RelativeLayout无法强制转换为android.widget.ListView ActivityThread.access$800（ActivityThread.java:135）。。。原因：java.lang.ClassCastException:您设置适配器了吗？我不知道这是什么意思：(