java - Android AlertDialog 因 NullPointerException 而崩溃

Question

我尝试将 HTML 放入 AlertDialog 中的 Listviewitem 中。因此我找到了一些 fragment 并最终将它们与我的 AlertDialog 一起设置。

AlertDialog.Builder builder = new AlertDialog.Builder(ChatActivity.this);
            builder.setTitle("Onlineliste");

            final LayoutInflater inflater = getLayoutInflater();
            final View convertView2 = (View) inflater.inflate(R.layout.costumdialog, null);
            builder.setView(convertView2);
            ListView lv = (ListView)convertView2.findViewById(R.id.customListView);
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(ChatActivity.this, R.layout.costumdialog, names)
                    {
                        @Override
                        public View getView(int position, View convertView, ViewGroup parent) 
                        {
                            View row;

                            if (null == convertView) {
                            row = inflater.inflate(R.layout.costumdialog, null);
                            } else {
                            row = convertView;
                            }

                            TextView tv = (TextView)row.findViewById(R.id.singlerow);
                            tv.setText(Html.fromHtml(getItem(position)));
                            //tv.setText(getItem(position));

                            return row;
                        }

                    };
                    lv.setAdapter(adapter);
            AlertDialog alert = builder.create();
            alert.show();

问题是，setAdapter() 强制应用程序因 NullPointerException 而崩溃

xml 文件等都存在，我认为它们没有问题。

谁能帮帮我？

编辑:

    06-12 07:26:45.537: E/AndroidRuntime(28036): FATAL EXCEPTION: main
06-12 07:26:45.537: E/AndroidRuntime(28036): java.lang.NullPointerException
06-12 07:26:45.537: E/AndroidRuntime(28036):    at com.flipflopdev.epvp_aj1987_chat.ChatActivity$1$1.getView(ChatActivity.java:82)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.AbsListView.obtainView(AbsListView.java:2075)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.ListView.measureHeightOfChildren(ListView.java:1476)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.ListView.onMeasure(ListView.java:1339)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.View.measure(View.java:12948)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5005)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.View.measure(View.java:12948)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5005)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.View.measure(View.java:12948)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5005)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.LinearLayout.measureVertical(LinearLayout.java:660)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.View.measure(View.java:12948)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5005)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.View.measure(View.java:12948)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5005)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.View.measure(View.java:12948)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5005)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2141)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.View.measure(View.java:12948)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1206)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2666)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.os.Looper.loop(Looper.java:156)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at android.app.ActivityThread.main(ActivityThread.java:4977)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at java.lang.reflect.Method.invokeNative(Native Method)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at java.lang.reflect.Method.invoke(Method.java:511)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-12 07:26:45.537: E/AndroidRuntime(28036):    at dalvik.system.NativeStart.main(Native Method)

R.layout.costumdialog

    <?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/customListView"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
</ListView>

ChatActivity 中的第 82 行

tv.setText(Html.fromHtml(getItem(position)));

自定义文本行.xml

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
     >

    <TextView
        android:id="@+id/singlerow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:paddingLeft="5dp">
    </TextView>

</RelativeLayout>

新代码:

AlertDialog.Builder builder = new AlertDialog.Builder(ChatActivity.this);
            builder.setTitle("Onlineliste");

            final LayoutInflater inflater = getLayoutInflater();
            //final View convertView2 = (View) inflater.inflate(R.layout.costumdialog, null);
            //builder.setView(convertView2);
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(ChatActivity.this, R.layout.costumdialog, names)
                    {
                        @Override
                        public View getView(int position, View convertView, ViewGroup parent) 
                        {
                            View row;

                            if (null == convertView) {
                            row = inflater.inflate(R.layout.text, null);
                            } else {
                            row = convertView;
                            }

                            TextView tv = (TextView)row.findViewById(R.id.singlerow);
                            tv.setText(Html.fromHtml(getItem(position)));
                            //tv.setText(getItem(position));

                            return row;
                        }

                    };
                    AlertDialog alert = builder.create();
                    ListView lv = (ListView)alert.findViewById(R.id.customListView);
                    lv.setAdapter(adapter); 


            alert.show();

Answer 1

您的 costomdialog.xml 没有 ID 为 singlerow 的 TextView。因此 tv 为空，当您调用 setText 时会导致 NullPointerException。

从您的评论看来，singlerow 是一个带有 textview 的布局

所以改变这个

ArrayAdapter<String> adapter = new ArrayAdapter<String>(ChatActivity.this, R.layout.costumdialog, names)

到

ArrayAdapter<String> adapter = new ArrayAdapter<String>(ChatActivity.this, R.layout.singlerow, names)

编辑:

ArrayAdapter<String> adapter = new ArrayAdapter<String>(ChatActivity.this, R.layout.customtextrow.xml, names)

完整示例

public class MainActivity extends Activity {

 String names[]={"A","B","C"};
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Onlineliste");

    final LayoutInflater inflater = getLayoutInflater();
    final View convertView2 = (View) inflater.inflate(R.layout.costomdialog, null);
    builder.setView(convertView2);
    ListView lv = (ListView)convertView2.findViewById(R.id.customListView);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, R.layout.costomdialog, names)
            {
                @Override
                public View getView(int position, View convertView, ViewGroup parent) 
                {
                    View row;

                    if (null == convertView) {
                    row = inflater.inflate(R.layout.customtextrow, null);
                    } else {
                    row = convertView;
                    }

                    TextView tv = (TextView)row.findViewById(R.id.singlerow);
                    tv.setText(names[position]);
                    //tv.setText(getItem(position));

                    return row;
                }

            };
            lv.setAdapter(adapter);
    AlertDialog alert = builder.create();
    alert.show();
     }
   }

xml是一样的，没有变化

快照:

编辑 2:

why does the Html.fromHtml not work? :/ See my names ArrayList final ArrayList names = new ArrayList();
String[] splitted = response.split("\|"); for(String name:splitted) { names.add(Html.fromHtml("" + name.split("\+")1 + "").toString()); }

拆分字符串并将其添加到数组列表中。在将文本设置为 textview 的同时设置 html。