android - 使用 ListView 选择项设置布局 - Android

Question

我有一个问题。

• 我想使用 ListView 中的选定项目重定向布局。
• 我想重定向的布局有空 View 对象，我想用所选 ListView 对象中的数据填充它们
• 但我做不到，我进行了调试，但在第 67 行出现错误单击 ListView 对象。我该怎么办？

请帮我做作业

这段代码在onCreate方法中代码:

    final ListView listView = (ListView) findViewById(R.id.lw_yemekTarifleri);
    customAdapter adapter = new customAdapter(this, yemekTarifleriList);
    listView.setAdapter(adapter);


    listView.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            //Log.i("OnClick", "position = " + position);


            ImageView yemekResim = (ImageView) findViewById(R.id.iw_yemekResim);
            TextView yemekIsim = (TextView) findViewById(R.id.tw_yemekIsim);
            TextView yemekSure = (TextView) findViewById(R.id.tw_yemekSure);
            TextView yemekMalzemeler = (TextView) findViewById(R.id.tw_malzemeler);
            TextView yemekTarif = (TextView) findViewById(R.id.tw_tarif);

            yemekTarifi secilenYemek = yemekTarifleriList.get(position);

            yemekResim.setImageResource(secilenYemek.getResim());        //(line 67)!!!!!!!!!!!!
            yemekIsim.setText(secilenYemek.getIsim());
            yemekSure.setText(secilenYemek.getHazirlanisSuresi());
            yemekMalzemeler.setText(secilenYemek.getMalzemeler());
            yemekTarif.setText(secilenYemek.getTarif());

            setContentView(R.layout.yemek_tarifi);



        }
    });

错误:

E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.erensayar_yemektarifi, PID: 13293 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageResource(int)' on a null object reference at com.example.erensayar_yemektarifi.anaSayfa_yemekTarifleri$1.onItemClick(anaSayfa_yemekTarifleri.java:67) at android.widget.AdapterView.performItemClick(AdapterView.java:318) at android.widget.AbsListView.performItemClick(AbsListView.java:1159) at android.widget.AbsListView$PerformClick.run(AbsListView.java:3136) at android.widget.AbsListView$3.run(AbsListView.java:4052) at android.os.Handler.handleCallback(Handler.java:873) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:193) at android.app.ActivityThread.main(ActivityThread.java:6669) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

代码已上传至github:github.com/erensayar/android

Answer 1

检查 secilenYemek 对象的值是否真的用值初始化。我的建议是在第 67 行之前设置一个调试点，即(第 66 行)并正确检查 secilenYemek 对象的值。因为它因此抛出空指针异常。