问题
I'm trying to add footer to ListView but application crashes after this line of code: getListView().addView(footerView);. I'm new to android and this is my first experience with ListView.
If is possible I need short explanation of inflate method.
Thanks!
ToDoListAdapter mAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create a new TodoListAdapter for this ListActivity's ListView
mAdapter = new ToDoListAdapter(getApplicationContext());
// Put divider between ToDoItems and FooterView
getListView().setFooterDividersEnabled(true);
//TODO - Inflate footerView for footer_view.xml file
TextView footerView = (TextView) getLayoutInflater().inflate(R.layout.footer_view, null);
//TODO - Add footerView to ListView
getListView().addView(footerView);
footerView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
log("Entered footerView.OnClickListener.onClick()");
//TODO - Attach Listener to FooterView. Implement onClick().
Intent startNewActivity = new Intent(null, AddToDoActivity.class);
startActivityForResult(startNewActivity, ADD_TODO_ITEM_REQUEST);
}
});
//TODO - Attach the adapter to this ListActivity's ListView
setListAdapter(mAdapter);
}
Log:
02-19 13:53:39.358: D/dalvikvm(1451): GC_FOR_ALLOC freed 68K, 6% free 3090K/3276K, paused 19ms, total 31ms
02-19 13:53:39.366: I/dalvikvm-heap(1451): Grow heap (frag case) to 4.196MB for 1127532-byte allocation
02-19 13:53:39.374: D/dalvikvm(1451): GC_FOR_ALLOC freed 2K, 5% free 4189K/4380K, paused 8ms, total 8ms
02-19 13:53:39.402: D/AndroidRuntime(1451): Shutting down VM
02-19 13:53:39.402: W/dalvikvm(1451): threadid=1: thread exiting with uncaught exception (group=0xa4d4db20)
02-19 13:53:39.414: E/AndroidRuntime(1451): FATAL EXCEPTION: main
02-19 13:53:39.414: E/AndroidRuntime(1451): Process: course.labs.todomanager, PID: 1451
02-19 13:53:39.414: E/AndroidRuntime(1451): java.lang.RuntimeException: Unable to start activity ComponentInfo{course.labs.todomanager/course.labs.todomanager.ToDoManagerActivity}: java.lang.UnsupportedOperationException: addView(View) is not supported in AdapterView
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.ActivityThread.access$800(ActivityThread.java:135)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.os.Handler.dispatchMessage(Handler.java:102)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.os.Looper.loop(Looper.java:136)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.ActivityThread.main(ActivityThread.java:5017)
02-19 13:53:39.414: E/AndroidRuntime(1451): at java.lang.reflect.Method.invokeNative(Native Method)
02-19 13:53:39.414: E/AndroidRuntime(1451): at java.lang.reflect.Method.invoke(Method.java:515)
02-19 13:53:39.414: E/AndroidRuntime(1451): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
02-19 13:53:39.414: E/AndroidRuntime(1451): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
02-19 13:53:39.414: E/AndroidRuntime(1451): at dalvik.system.NativeStart.main(Native Method)
02-19 13:53:39.414: E/AndroidRuntime(1451): Caused by: java.lang.UnsupportedOperationException: addView(View) is not supported in AdapterView
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.widget.AdapterView.addView(AdapterView.java:452)
02-19 13:53:39.414: E/AndroidRuntime(1451): at course.labs.todomanager.ToDoManagerActivity.onCreate(ToDoManagerActivity.java:56)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.Activity.performCreate(Activity.java:5231)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
02-19 13:53:39.414: E/AndroidRuntime(1451): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
02-19 13:53:39.414: E/AndroidRuntime(1451): ... 11 more
Edit:
Thanks, fixed that problem but now I it seems there is issue somewhere in click listener.
Log:
02-19 14:19:02.346: I/Lab-UserInterface(1731): Entered footerView.OnClickListener.onClick()
02-19 14:19:02.346: D/AndroidRuntime(1731): Shutting down VM
02-19 14:19:02.346: W/dalvikvm(1731): threadid=1: thread exiting with uncaught exception (group=0xa4d4db20)
02-19 14:19:02.350: E/AndroidRuntime(1731): FATAL EXCEPTION: main
02-19 14:19:02.350: E/AndroidRuntime(1731): Process: course.labs.todomanager, PID: 1731
02-19 14:19:02.350: E/AndroidRuntime(1731): java.lang.NullPointerException
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.content.ComponentName.<init>(ComponentName.java:77)
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.content.Intent.<init>(Intent.java:3813)
02-19 14:19:02.350: E/AndroidRuntime(1731): at course.labs.todomanager.ToDoManagerActivity$1.onClick(ToDoManagerActivity.java:65)
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.view.View.performClick(View.java:4438)
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.view.View$PerformClick.run(View.java:18422)
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.os.Handler.handleCallback(Handler.java:733)
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.os.Handler.dispatchMessage(Handler.java:95)
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.os.Looper.loop(Looper.java:136)
02-19 14:19:02.350: E/AndroidRuntime(1731): at android.app.ActivityThread.main(ActivityThread.java:5017)
02-19 14:19:02.350: E/AndroidRuntime(1731): at java.lang.reflect.Method.invokeNative(Native Method)
02-19 14:19:02.350: E/AndroidRuntime(1731): at java.lang.reflect.Method.invoke(Method.java:515)
02-19 14:19:02.350: E/AndroidRuntime(1731): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
02-19 14:19:02.350: E/AndroidRuntime(1731): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
02-19 14:19:02.350: E/AndroidRuntime(1731): at dalvik.system.NativeStart.main(Native Method)
回答1:
Change
getListView().addView(footerView);To
getListView().addFooterView(footerView);Explanation for inflate function:
LayoutInflater().inflate()just converts a layout xml into an actual View structure.Your second issue:
Have a look at your click listener:
Intent startNewActivity = new Intent(null, AddToDoActivity.class);You cannot start an Intent with null as the context (the first argument)
Change to this:
Intent startNewActivity = new Intent(ToDoManagerActivity.this, AddToDoActivity.class);
回答2:
short explanation of inflate method: Instantiates a layout XML file into its corresponding View objects. see LayoutInflator
来源：https://stackoverflow.com/questions/21883012/crash-after-adding-footer-to-listview