Question

我无法点击列表视图来传递新活动。请指教我如何解决这个问题。

这里是我的代码

// set UI
        setContentView(R.layout.show_permission);

        //get list from background
        show = getListView();

        //object for permission list
        permission_list = new ArrayList<HashMap<String,String>>();

        // get uid from main activity
        Intent i = getIntent();
        uid = i.getStringExtra(TAG_UID);

        // get data from background thread
        new GetPermission().execute();



        show.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // TODO Auto-generated method stub
                //getting item from list Item
                String project_id = ((TextView) view.findViewById(R.id.report_id)).getText().toString(); <---error here
                String project_name = ((TextView) view.findViewById(R.id.pro_name)).getText().toString();

                Intent in = getIntent();
                //send report_id to next activity
                in.putExtra(TAG_PROJECT_ID, project_id);
                in.putExtra(TAG_PROJECT_NAME, project_name);
                in.putExtra(TAG_UID, uid);
                setResult(100, in);

                finish();
            }
        });

并在这里登录cat show

    09-25 15:41:27.510: E/AndroidRuntime(1457): FATAL EXCEPTION: main
09-25 15:41:27.510: E/AndroidRuntime(1457): java.lang.NullPointerException
09-25 15:41:27.510: E/AndroidRuntime(1457):     at com.example.androidhive.ProjectPermission$1.onItemClick(ProjectPermission.java:82)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.widget.AdapterView.performItemClick(AdapterView.java:298)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.widget.AbsListView.performItemClick(AbsListView.java:1086)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.widget.AbsListView$PerformClick.run(AbsListView.java:2855)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.widget.AbsListView$1.run(AbsListView.java:3529)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.os.Handler.handleCallback(Handler.java:615)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.os.Handler.dispatchMessage(Handler.java:92)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.os.Looper.loop(Looper.java:137)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at android.app.ActivityThread.main(ActivityThread.java:4745)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at java.lang.reflect.Method.invokeNative(Native Method)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at java.lang.reflect.Method.invoke(Method.java:511)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-25 15:41:27.510: E/AndroidRuntime(1457):     at dalvik.system.NativeStart.main(Native Method)

感谢您的帮助！

Answer 1

之一

((TextView) view.findViewById(R.id.report_id)).getText().toString();

为空。

观点：没有意义
findViewById（R.id.report_id））：您确定项目布局中存在此视图吗？
getText（）：report_id视图的文本可以为null

Answer 2

而不是使用

String project_id = ((TextView) view.findViewById(R.id.report_id)).getText().toString();

试试这个：

<强> mTextView = (TextView)findViewById(R.id.report_id);

<强> String project_id = mTextView.getText().toString();

Answer 3

创建一个textview变量说tv，然后

tv =（TextView）findViewById（R.id.report_id）;

将'tv'附加到其ID后，尝试使用

从中获取文本

String str = tv.getText（）。toString（）;

在'Toast'中显示字符串'str'，以确定它是否不包含空值，如果这不起作用，请在此处发布代码。

Answer 4

尝试使用以下方法：

  String project_id = ((TextView) view.getChildAt(index of project id view)).getText().toString(); 

  String project_name = ((TextView) view.getChildAt(index of project name view)).getText().toString();

例如，如果项目ID文本视图是列表项视图中的第一个视图，则将0作为项目ID的索引传递。

Answer 5

感谢所有回复，我找到了解决方案来解决这个问题

setContentView(R.layout.show_permission);

        ListView lv = getListView();

        Intent i = getIntent();
        uid = i.getStringExtra(TAG_UID);


        //report list
        permission_list = new ArrayList<HashMap<String,String>>();
        //load report in background
        new GetPermission().execute();

        // listView OnClicklistener
        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
                // TODO Auto-generated method stub
                //getting item from list Item
                String project_name = ((TextView) view.findViewById(R.id.pro_name)).getText().toString();

                // pass data to edit
                Intent edit = new Intent(getApplicationContext(), TimeReport.class);

                //send report_id to next activity
                edit.putExtra(TAG_PROJECT_NAME, project_name);
                edit.putExtra(TAG_UID, uid);

                startActivityForResult(edit, 100);
            }

ListView onItemClick：NullPointerException检索视图

5 个答案: