Question

创建ListView时遇到问题，因为我无法启动新活动。这是代码

public class MainActivity extends Activity {

    static final String[] modules = new String[] { "Modulo 442", "Modulo 433" };


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ArrayAdapter<String> codeLearnArrayAdapter = new ArrayAdapter<String>(
                this, android.R.layout.simple_list_item_1, modules);
        ListView codeLearnLessons = (ListView) findViewById(R.id.listView);
        codeLearnLessons.setAdapter(codeLearnArrayAdapter);
    }

    protected void onListItemClick(ListView l, View v, int pos, long id) {

        if (pos==0){
            Intent intent = new Intent(this, Module442.class);
            startActivity(intent);
        }
        else if (pos==1){
            Intent intent = new Intent(this, Module433.class);
            startActivity(intent);
        }

    }
}

这是布局文件的代码：

<RelativeLayout 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" >



    <ListView android:id="@+id/listView"
              android:layout_height="match_parent"
              android:layout_width="match_parent"/>

</RelativeLayout>

当我点击选项时，没有任何事情发生......

这是另一项新活动：

public class Module442 extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_module442);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.module442, menu);
        return true;
    }

}

感谢您的帮助!!!!

解决

公共类MainActivity扩展了Activity {

/** Called when the activity is first created. */

ListView list;
private String array[] = { "Modulo 442", "Modulo 433" };

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    list = (ListView) findViewById(R.id.list);
    list.setAdapter(new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, array));

    list.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> paramAdapterView,
                View paramView, int position, long paramLong) {
            switch (position) {
            case 0:
                Intent newActivity0 = new Intent(MainActivity.this,
                        Module442.class);
                startActivity(newActivity0);
                break;
            case 1:
                Intent newActivity1 = new Intent(MainActivity.this,
                        Module433.class);
                startActivity(newActivity1);
                break;
            }
        }
    });
}

}

Answer 1

您尚未在Listener上设置ListView。

ListView codeLearnLessons = (ListView) findViewById(R.id.listView);
codeLearnLessons.setAdapter(codeLearnArrayAdapter);
codeLearnLessons.setOnItemClickListener(this);  // here

然后你会想要以这种方式将它添加到你的类声明中

public class MainActivity extends Activity implements OnItemClickListener{

您应该将@Override添加到onItemClick()

@Override
protected void onListItemClick(ListView l, View v, int pos, long id) {

Answer 2

你想这样做：

codeLearnLessons.setOnItemClickListener(new OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
        long id) {

    if (position ==0){
        Intent intent = new Intent(this, Module442.class);
        startActivity(intent);
    }
    else if (position ==1){
        Intent intent = new Intent(this, Module433.class);
        startActivity(intent);
    }

    }
});

使用ListView开始新活动

2 个答案: