列表视图中的Android烤面包消息
问题描述：
-
和表行的onclick显示敬酒消息
And onclick of list row display a toast message
我有错误
我能够显示在列表视图中的元素，但是，点击列表项的我收到错误的
MainActivity.java
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String Names[]={"Mango","Banana","grapes"};
ListView LV=(ListView) findViewById(R.id.listView1);
ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,R.layout.list_item,R.id.textView1,Names);
LV.setAdapter(adapter);
LV.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View v, int arg2,
long arg3) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), ((TextView) v).getText(), Toast.LENGTH_SHORT).show();
}
});
}
}
list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:padding="5dp"
android:text="TextView"
android:textStyle="italic|bold" />
</LinearLayout>
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ListView
android:id="@+id/listView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_weight="1" >
</ListView>
</LinearLayout>
LOG
08-19 18:29:18.621: D/AndroidRuntime(692): Shutting down VM
08-19 18:29:18.621: W/dalvikvm(692): threadid=1: thread exiting with uncaught exception (group=0x40015560)
08-19 18:29:18.921: E/AndroidRuntime(692): FATAL EXCEPTION: main
08-19 18:29:18.921: E/AndroidRuntime(692): java.lang.ClassCastException: android.widget.LinearLayout
08-19 18:29:18.921: E/AndroidRuntime(692): at com.example.listviews.MainActivity$1.onItemClick(MainActivity.java:34)
08-19 18:29:18.921: E/AndroidRuntime(692): at android.widget.AdapterView.performItemClick(AdapterView.java:284)
08-19 18:29:18.921: E/AndroidRuntime(692): at android.widget.ListView.performItemClick(ListView.java:3513)
08-19 18:29:18.921: E/AndroidRuntime(692): at android.widget.AbsListView$PerformClick.run(AbsListView.java:1812)
08-19 18:29:18.921: E/AndroidRuntime(692): at android.os.Handler.handleCallback(Handler.java:587)
08-19 18:29:18.921: E/AndroidRuntime(692): at android.os.Handler.dispatchMessage(Handler.java:92)
08-19 18:29:18.921: E/AndroidRuntime(692): at android.os.Looper.loop(Looper.java:123)
08-19 18:29:18.921: E/AndroidRuntime(692): at android.app.ActivityThread.main(ActivityThread.java:3683)
08-19 18:29:18.921: E/AndroidRuntime(692): at java.lang.reflect.Method.invokeNative(Native Method)
08-19 18:29:18.921: E/AndroidRuntime(692): at java.lang.reflect.Method.invoke(Method.java:507)
08-19 18:29:18.921: E/AndroidRuntime(692): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-19 18:29:18.921: E/AndroidRuntime(692): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-19 18:29:18.921: E/AndroidRuntime(692): at dalvik.system.NativeStart.main(Native Method)
08-19 18:29:23.481: I/Process(692): Sending signal. PID: 692 SIG: 9
08-19 18:35:01.833: D/AndroidRuntime(726): Shutting down VM
08-19 18:35:01.833: W/dalvikvm(726): threadid=1: thread exiting with uncaught exception (group=0x40015560)
08-19 18:35:01.851: E/AndroidRuntime(726): FATAL EXCEPTION: main
08-19 18:35:01.851: E/AndroidRuntime(726): java.lang.ClassCastException: android.widget.LinearLayout
08-19 18:35:01.851: E/AndroidRuntime(726): at com.example.listviews.MainActivity$1.onItemClick(MainActivity.java:34)
08-19 18:35:01.851: E/AndroidRuntime(726): at android.widget.AdapterView.performItemClick(AdapterView.java:284)
08-19 18:35:01.851: E/AndroidRuntime(726): at android.widget.ListView.performItemClick(ListView.java:3513)
08-19 18:35:01.851: E/AndroidRuntime(726): at android.widget.AbsListView$PerformClick.run(AbsListView.java:1812)
08-19 18:35:01.851: E/AndroidRuntime(726): at android.os.Handler.handleCallback(Handler.java:587)
08-19 18:35:01.851: E/AndroidRuntime(726): at android.os.Handler.dispatchMessage(Handler.java:92)
08-19 18:35:01.851: E/AndroidRuntime(726): at android.os.Looper.loop(Looper.java:123)
08-19 18:35:01.851: E/AndroidRuntime(726): at android.app.ActivityThread.main(ActivityThread.java:3683)
08-19 18:35:01.851: E/AndroidRuntime(726): at java.lang.reflect.Method.invokeNative(Native Method)
08-19 18:35:01.851: E/AndroidRuntime(726): at java.lang.reflect.Method.invoke(Method.java:507)
08-19 18:35:01.851: E/AndroidRuntime(726): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-19 18:35:01.851: E/AndroidRuntime(726): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-19 18:35:01.851: E/AndroidRuntime(726): at dalvik.system.NativeStart.main(Native Method)
克服任何想法此
答
正如你可以从logcat的看，你得到类转换异常，因为你想投的线性布局是根视图（视图V在这种情况下， ）为您的列表项到一个TextView。
As you can see from the logcat, You are getting class cast exception because you are trying to cast linear layout which is the root view (View v in this case) for your listitem to a TextView.
你应该做的是如下：
LV.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View v, int arg2,
long arg3) {
//here v is your ListItem's layout.
TextView tv = (TextView) v.findViewById(R.id.textView1);
Toast.makeText(getApplicationContext(), tv.getText().toString(), Toast.LENGTH_SHORT).show();
}
});