Question

我正在尝试将一个数组列表放入列表视图，并在屏幕上显示一个在xml文件中声明为onClick的按钮。我按照互联网上的教程进行了操作，但不知怎的，它没有工作，应用程序在点击按钮后就停止了。

这就是onclick方法上的按钮的样子：

public void sendDestination_zhu(View v){
    tryconnect tc= new tryconnect();
    List<String> sR=tc.doInBackground();
    ListView list = (ListView)findViewById(R.id.listView);
    ArrayAdapter<String> adapter=new ArrayAdapter<String>    (FragmentHandler.this,R.layout.single_row,R.id.parkingplace,sR);
    list.setAdapter(adapter);
}

列表视图xml是这样的：

<ListView
    android:id="@+id/listView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/showingmessage" >

以下是单行的xml：

<TextView
    android:id="@+id/parkingplace"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text=""
    android:textAppearance="?android:attr/textAppearanceLarge" />

logcat的：

05-23 09:42:04.130: E/Cursor(29553): 2
05-23 09:42:04.330: E/Cursor(29553): i1
05-23 09:42:04.330: E/AndroidRuntime(29553): FATAL EXCEPTION: main
05-23 09:42:04.330: E/AndroidRuntime(29553): java.lang.IllegalStateException: Could not execute    method of the activity
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.view.View$1.onClick(View.java:3838)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.view.View.performClick(View.java:4475)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.view.View$PerformClick.run(View.java:18786)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.os.Handler.handleCallback(Handler.java:730)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.os.Looper.loop(Looper.java:137)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.app.ActivityThread.main(ActivityThread.java:5493)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at java.lang.reflect.Method.invokeNative(Native Method)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at java.lang.reflect.Method.invoke(Method.java:525)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at dalvik.system.NativeStart.main(Native Method)
05-23 09:42:04.330: E/AndroidRuntime(29553): Caused by: java.lang.reflect.InvocationTargetException
05-23 09:42:04.330: E/AndroidRuntime(29553):    at java.lang.reflect.Method.invokeNative(Native Method)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at java.lang.reflect.Method.invoke(Method.java:525)
05-23 09:42:04.330: E/AndroidRuntime(29553):    at android.view.View$1.onClick(View.java:3833)
05-23 09:42:04.330: E/AndroidRuntime(29553):    ... 11 more
05-23 09:42:04.330: E/AndroidRuntime(29553): Caused by: java.lang.NullPointerException
05-23 09:42:04.330: E/AndroidRuntime(29553):    at com.smartparking.FragmentHandler.sendDestination_zhu(FragmentHandler.java:824)
05-23 09:42:04.330: E/AndroidRuntime(29553):    ... 14 more

ListView无法在onClick方法中显示代码

0 个答案: