Question

我想知道为什么当我运行我的应用程序并尝试单击每日预测选项时，我得到以下logcat。

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

这是我的日常生活活动

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：抱歉忘记发布这里！这里是活动日常预测

'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();
    }
}
'

我是否需要以不同方式声明ListActivity？

Answer 1

将ListView ID的ID设为@android:id/list，然后onCreate方法

 @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);
    }

扩展ListActivity时的类强制转换异常

1 个答案: