使用列表视图选择项设置布局 - Android

Question

我有问题。

我想在列表视图中使用所选项目进行重定向布局。
我想重定向的布局有空视图对象，我想用所选列表视图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 行出现错误单击列表视图对象。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.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$PerformClick.run(AbsListView.java:3136) at android.widget.AbsListView.run(AbsListView.java:4052) at android.os.Handler.handleCallback(Handler.java:873) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:193) at android.app.ActivityThread.main(ActivityThread.java:6669) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$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。

Answer 2

试试这个

  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);

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);



        yemekTarifi secilenYemek = yemekTarifleriList.get(position);

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

        setContentView(R.layout.yemek_tarifi);



    }
});

Answer 3

我发现了我的问题。我忘记为我的目标布局打开 activity class。我创建了布局，但没有创建 activity。然后，我应该从 listview onclick activity.

发送其他 activity（我的布局适配器）数据

而且我们应该使用意图像这样：

//这个区块已经有

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

//当我们点击列表视图中的元素时（发件人）

    listView.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            setContentView(R.layout.yemek_tarifi_yemek_tarifleri);
            yemekTarifi secilenYemek = yemekTarifleriList.get(position);

            //Log.d("OnClick", "position = " + yemekTarifleriList.get(position));


            //Elemanları layouta bastırmak için bu verileri öbür activity'e yani istediğimiz layouta göndermeliyiz. O da intent.putextra ile oluyor.
            Intent intent = new Intent(getApplicationContext(), yemekTarifiAdapter.class);


            intent.putExtra("isim", secilenYemek.getIsim());
            intent.putExtra("malzemeler", secilenYemek.getMalzemeler());
            intent.putExtra("tarif", secilenYemek.getTarif());
            intent.putExtra("sure", secilenYemek.getHazirlanisSuresi());

            startActivity(intent);

        }
    });

//这个块目标loyout的class.(适配器)

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

    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);


    //Receiver 
    String isim = getIntent().getExtras().getString("isim");
    String malzemeler = getIntent().getExtras().getString("malzemeler");
    String tarif = getIntent().getExtras().getString("tarif");
    int sure = getIntent().getExtras().getInt("sure");



    yemekIsim.setText(isim);
    yemekSure.setText(String.valueOf(sure));
    yemekMalzemeler.setText(malzemeler);
    yemekTarif.setText(tarif);



}//OnCreate Sonu

感谢所有帮助过的人。

如果想查看所有新代码：github/erensayar/android

使用列表视图选择项设置布局 - Android

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