Question

我已经构建了一个自定义列表项，通过膨胀每个列表项来替换android的简单列表项。自定义列表正常运行，它由image view和text view组成。

我的问题是，当我点击列表项后尝试启动新的activity时，即使应用程序不会崩溃也没有任何反应。那么，有没有办法使用列表视图启动活动???

public class activityone extends ListActivity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activitylayout);

        setListAdapter(new MyAdapter(this, android.R.layout.simple_list_item_1,      R.id.textView1, 
                           getResources().getStringArray(R.array.names)));

    }
    public void onListItemClick(ListView l, View v, int position,
                long id) {
            // TODO Auto-generated method stub
            super.onListItemClick(l, v, position, id);

            Object o = this.getListAdapter().getItem(position);

            if(getSelectedItemPosition() == 0){
                Intent intent = new Intent(activityone.this,no1.class);
                startActivity(intent);
            }
                                   .
                                   .
                                   . 
                                   .

    }

    private class MyAdapter extends ArrayAdapter<String>{

        public MyAdapter(Context context, int resource, int textViewResourceId,
                String[] strings) {
            super(context, textViewResourceId, strings);
            // TODO Auto-generated constructor stub
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View row = inflater.inflate(R.layout.list_item, parent, false);

            String[] items = getResources().getStringArray(R.array.names);

            ImageView iv = (ImageView) row.findViewById(R.id.imageView1);
            TextView tv = (TextView) row.findViewById(R.id.textView1);

            tv.setText(items[position]);


            if(items[position].equals("john")){
                iv.setImageResource(R.drawable.john);
            }
                                   .
                                   .
                                   . 
                                   .

            return row;
        }
    }
}

这是no1类

public class no1 extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.name_profile);

        CharSequence t1 = "Name: john";
        CharSequence t2 = "Age: 31";
        CharSequence t3 = "Nationality: Saudi";
        CharSequence t4 = "Number: 765646454";

        ImageView iv = (ImageView) findViewById(R.drawable.imageView1);
        TextView tv1 = (TextView) findViewById(R.id.textView1);
        TextView tv2 = (TextView) findViewById(R.id.textView2);
        TextView tv3 = (TextView) findViewById(R.id.textView3);
        TextView tv4 = (TextView) findViewById(R.id.textView4);

        iv.setImageResource(R.drawable.john);

        tv1.setText(t1);
        tv2.setText(t2);
        tv3.setText(t3);
        tv4.setText(t4);
    }
}

是的，我的activities已添加到manifest xml file。

感谢您的帮助。

@Pineet Shukla我不知道怎么做这个我放了一个断点但我无法调试我是eclipse环境的新手你能解释一下吗

@Divyesh

我编辑了代码，当我在此处按下列表项时，应用程序崩溃了是Logcat跟踪

09-17 10:10:57.686: ERROR/AndroidRuntime(365): FATAL EXCEPTION: main
09-17 10:10:57.686: ERROR/AndroidRuntime(365): java.lang.RuntimeException: Unable to        start activity ComponentInfo{com.abc.act/com.abc.act.no1}: java.lang.NullPointerException
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at    android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)

09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.os.Looper.loop(Looper.java:123)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.app.ActivityThread.main(ActivityThread.java:4627)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at java.lang.reflect.Method.invokeNative(Native Method)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at java.lang.reflect.Method.invoke(Method.java:521)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at dalvik.system.NativeStart.main(Native Method)
09-17 10:10:57.686: ERROR/AndroidRuntime(365): Caused by: java.lang.NullPointerException
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at com.abc.act.no1.onCreate(no1.java:31)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-17 10:10:57.686: ERROR/AndroidRuntime(365):     ... 11 more

Answer 1

您没有有效地使用此API，您应该切换到SimpleAdapter，因为处理更复杂的List Item布局和数据绑定。您需要有效地使用列表的基础数据，而不是创建难以处理的分支语句。

自定义列表开始新活动？

1 个答案: