不知道为什么我在下面的代码中得到一个ClassCastException.将ListActivity更改为活动可以纠正错误,但是我想要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:
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- xmlns:tools="http://schemas.android.com/tools"
- android:id="@android:id/list"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:orientation="horizontal" >
- <LinearLayout
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:orientation="vertical" >
- <!-- Name Label -->
- <TextView
- android:id="@+id/vehicleType"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:textColor="#43bd00"
- android:textSize="16sp"
- android:textStyle="bold"
- android:paddingTop="6dip"
- android:text="Mobile1"
- android:paddingBottom="2dip" />
- <!-- Description Label -->
- <TextView
- android:id="@+id/vehicleColor"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:textColor="#acacac"
- android:text="Mobile2"
- android:paddingBottom="2dip" />
- <LinearLayout
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:orientation="horizontal" >
- <!-- Cost Label -->
- <TextView
- android:id="@+id/fuel"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:textColor="#000000"
- android:gravity="left"
- android:textStyle="bold"
- android:text="Mobile3" />
- <!-- Price Label -->
- <TextView
- android:id="@+id/treadType"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:textColor="#acacac"
- android:text="Mobile4"
- android:paddingBottom="2dip" />
- </LinearLayout>
- </LinearLayout>
- <ListView
- android:id="@android:id/list"
- android:layout_width="match_parent"
- android:layout_height="wrap_content" >
- </ListView>
- </LinearLayout>
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
解决方法
你的问题是你的布局的根源
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- xmlns:tools="http://schemas.android.com/tools"
- android:id="@android:id/list"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:orientation="horizontal" >
你给它android:id =“@ android:id / list”的机器保留ListView小部件的id.改变它在别的东西.例如
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- xmlns:tools="http://schemas.android.com/tools"
- android:id="@+id/my_linear_layout"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:orientation="horizontal" >