Question

这是我在主要活动中的代码

 public class MainActivity extends ListActivity {

    private String [] mainScreenList = {"Portal","Settings","Help","About"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ArrayAdapter<String> mainScreen = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_activated_1, android.R.id.text1,mainScreenList);
        ListView lv = (ListView) findViewById(R.id.listView);
        lv.setAdapter(mainScreen);
    }
    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);
        Object o = this.getListAdapter().getItem(position);
        String pen = o.toString();
        Toast.makeText(this, "You have chosen the pen: " + " " + pen, Toast.LENGTH_LONG).show();
        //get selected items
       /* if(position==0)
        {
            Intent i = new Intent(this, DataEntryActivity.class);
            startActivity(i);
        }else if(position==1)
        {
            Intent i = new Intent(this, DataEntryActivity.class);
            startActivity(i);
        }else if(position==2)
        {
            Intent i = new Intent(this, DataEntryActivity.class);
            startActivity(i);
        }else if(position==3)
        {
            Intent i = new Intent(this, DataEntryActivity.class);
            startActivity(i);
        }*/
    }
}

目前我只是想显示所选列表视图项的名称。

这是XML代码

<?xml version="1.0" encoding="utf-8"?>
<ListView
    android:id="@android:id/list"
    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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="com.example.bernine.practicalsessions.MainActivity">
    <ListView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/listView"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"

        />
</ListView>

在运行应用程序时，它会说＆＃34;不幸的是应用程序已经停止。＆＃34;

Answer 1

签出activity_main.xml布局文件后。您已将ListView包含在另一个ListView中。这是无效的。

在ListView之类的任何容器中加入LinearLayout ,RelativeLayout , etc.。对于ListView，您应该将ID用作@android:id/list。一旦查看此样本布局。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

        <ListView
            android:id="@android:id/list"
            android:layout_height="wrap_content"
            android:layout_width="match_parent">
        </ListView>

    </LinearLayout>

ListActivity错误：“很遗憾，您的应用已停止”

1 个答案: