Question

03-19 23:38:21.952: E/AndroidRuntime(400): FATAL EXCEPTION: main
03-19 23:38:21.952: E/AndroidRuntime(400): java.lang.NullPointerException
03-19 23:38:21.952: E/AndroidRuntime(400):  at net.website.custom_listview.Lazy_Adapter_Custom_Listview$1.onClick(Lazy_Adapter_Custom_Listview.java:75)
03-19 23:38:21.952: E/AndroidRuntime(400):  at android.view.View.performClick(View.java:2485)
03-19 23:38:21.952: E/AndroidRuntime(400):  at android.view.View$PerformClick.run(View.java:9080)
03-19 23:38:21.952: E/AndroidRuntime(400):  at android.os.Handler.handleCallback(Handler.java:587)
03-19 23:38:21.952: E/AndroidRuntime(400):  at android.os.Handler.dispatchMessage(Handler.java:92)
03-19 23:38:21.952: E/AndroidRuntime(400):  at android.os.Looper.loop(Looper.java:123)
03-19 23:38:21.952: E/AndroidRuntime(400):  at android.app.ActivityThread.main(ActivityThread.java:3683)
03-19 23:38:21.952: E/AndroidRuntime(400):  at java.lang.reflect.Method.invokeNative(Native Method)
03-19 23:38:21.952: E/AndroidRuntime(400):  at java.lang.reflect.Method.invoke(Method.java:507)
03-19 23:38:21.952: E/AndroidRuntime(400):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-19 23:38:21.952: E/AndroidRuntime(400):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-19 23:38:21.952: E/AndroidRuntime(400):  at dalvik.system.NativeStart.main(Native Method)

我不确定下面的代码有什么问题，但我得到null异常（艺术家）

ps：textview确实存在于布局文件中。

 public View getView(int position, View convertView, ViewGroup parent) {
        View vi=convertView;
        if(convertView==null)
            vi = inflater.inflate(R.layout.list_row_custom_listview, null);


        TextView artist = (TextView)vi.findViewById(R.id.artist); // artist name 
        TextView link = (TextView)vi.findViewById(R.id.txtLink);


        // Setting all values in listview 
        artist.setText(song.get(Main_Activity_Custom_Listview.KEY_TITLE_ENGLISH));

        link.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
        int duration = Toast.LENGTH_SHORT;


        TextView tx =(TextView)v.findViewById(R.id.txtLink); //null exception???
        TextView artist = (TextView)v.findViewById(R.id.artist); // null exception???

        Log.v("link>>", "onItemClick at position" + artist.getText());

        //Toast toast = Toast.makeText(PlayListActivity.this, tx.getText(), duration);
        //toast.show(); 
        }
    }); 
        return vi;
    }

Answer 1

public View getView(final int position, View convertView, ViewGroup parent) {
    .
    .
    .

    vi.findViewById(R.id.dots).setOnClickListener(new OnClickListener() {

       @Override
       public void onClick(View v) {

            MessagesActivity.list.getChildAt(((int) MessagesActivity.list.getItemIdAtPosition(position))-MessagesActivity.list.getFirstVisiblePosition()).findViewById(R.id.top_header).setBackgroundResource(R.layout.list_selector);

       }

    .
    .
    .
    }

也许这可以帮到你

适合我

Answer 2

问题在于此行[{1}}，您为TextView link.setOnClickListener(....设置了OnClickListener，因此TextView将成为传递给link回调的View参数，你肯定无法从中获取（findViewById）你的艺术家视图。

我认为你打算做onClick。即便如此，我认为你打算做的是适当的，因为你可以覆盖ListView的vi.setOnClickListener()回调，你不需要为每个回调设置OnClickListener。你的listview项目就像你在代码片段中所做的那样。

修改

看看AdapterView.OnItemClickListener。

然后你会做这样的事情：

onItemClick

Answer 3

我想你在另一篇文章中提到了类似的东西。我曾提到你不应该这样做。您需要阅读onClick（）功能。

public View getView(int position, View convertView, ViewGroup parent) {
    View vi=convertView;
    if(convertView==null)
        vi = inflater.inflate(R.layout.list_row_custom_listview, null);

    //Make them final so that you can access them in your onClick()
    final TextView artist = (TextView)vi.findViewById(R.id.artist); // artist name 
    final TextView tx =(TextView)vi.findViewById(R.id.txtLink); 
    TextView link = (TextView)vi.findViewById(R.id.txtLink);



    // Setting all values in listview 
    artist.setText(song.get(Main_Activity_Custom_Listview.KEY_TITLE_ENGLISH));

    link.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
        int duration = Toast.LENGTH_SHORT;

        Log.v("link>>", "onItemClick at position" + artist.getText());

        }
    }); 
    return vi;
}

getView使用自定义列表视图获取null异常

3 个答案: