java.lang.ClassCastException:android.widget.LinearLayout无法强制转换为android.widget.ListView

不知道为什么我在下面的代码中得到ClassCastException.将ListActivity更改为Activity会更正错误但我想要ListActivity,因为这是我正在尝试构建的更大代码的一部分.任何帮助将不胜感激.谢谢

MainActivity.java

package com.example.debug;

import android.app.ListActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;


public class MainActivity extends ListActivity {

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


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

activity_main.xml中:

堆栈跟踪

FATAL EXCEPTION: main
Process: com.example.debug, PID: 1370
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.debug/com.example.debug.MainActivity}: java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.ListView
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
    at android.app.ActivityThread.access$800(ActivityThread.java:135)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5017)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.ListView
    at android.app.ListActivity.onContentChanged(ListActivity.java:241)
    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:293)
    at android.app.Activity.setContentView(Activity.java:1929)
    at com.example.debug.MainActivity.onCreate(MainActivity.java:14)
    at android.app.Activity.performCreate(Activity.java:5231)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
    ... 11 more

Blackbelt.. 14

你的问题是你的布局的根

你给它的 android:id="@android:id/list"机器人为ListView小部件保留的id .用其他东西改变它.例如

Shivam Verma.. 5

在ListActivity中,android会查找具有android:id="@android:id/list"并期望ListView 的小部件,但在您的情况下,它会找到根LinearLayout并尝试将其强制 转换为ListView,因此异常:

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

要解决这个问题,您只需要提供Blackbelt提到的不同ID.

你的问题是你的布局的根

你给它的 android:id="@android:id/list"机器人为ListView小部件保留的id .用其他东西改变它.例如

在ListActivity中,android会查找具有android:id="@android:id/list"并期望ListView 的小部件,但在您的情况下,它会找到根LinearLayout并尝试将其强制 转换为ListView,因此异常:

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

要解决这个问题,您只需要提供Blackbelt提到的不同ID.