Android AlertDialog与NullPointerException崩溃

时间：2014-06-12 05:30:38

标签： java android nullpointerexception alertdialog

我尝试将HTML放入AlertDialog中的Listviewitem中。 因此我找到了一些片段，最后将我的AlertDialog设置在一起。

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()迫使应用程序崩溃并出现NullPointerException

xml文件等都存在，我认为它们没有问题。

任何人都可以帮助我吗？

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)));

customtextrow.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();

3 个答案:

答案 0 :(得分：1)

您的costomdialog.xml没有身份TextView的{​​{1}}。因此singlerow为空，当您调用setText时会导致tv。

从你的评论看起来，singlerow是一个带有textview的布局

所以改变这个

NullPointerException

到

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

编辑：

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

完整示例

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

xml是相同的无变化

对齐：

enter image description here

编辑2：

  

为什么Html.fromHtml不起作用？ ：/看我的名字ArrayList final   ArrayList names = new ArrayList（）;
     串[]   splitted = response.split（“\ |”）; for（String name：splitted）{                     names.add（Html.fromHtml（“”+ name.split（“\ +”）1 +“”）。toString（））; }

拆分String将其添加到arraylist。在将文本设置为textview时设置html。

答案 1 :(得分：1)

问题是你在没有任何TextView的情况下膨胀R.layout.costumdialog你不需要在ListView中扩充ListView，只需要将TextView添加到R.layout.costumdialog

中

创建名为text.xml

的新布局 
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/singlerow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView" />

</LinearLayout>

将其更改为此

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

这不是将适配器设置为ListView的正确方法，您需要从AlertDialog获取ListView引用以使其能够使用适配器。

示例：

<强>错 

      ListView lv = (ListView)convertView2.findViewById(R.id.customListView);

从右 

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

完整代码：

  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);

        AlertDialog alert = builder.create();

        ListView lv = (ListView)alert.findViewById(R.id.customListView);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(ChatActivity.this, R.layout.text, names)
                {
                    @Override
                    public View getView(int position, View convertView, ViewGroup parent) 
                    {
                        View row = super.getView(position, convertView, parent);
                        TextView tv = (TextView)row.findViewById(R.id.singlerow);
                        tv.setText(Html.fromHtml(getItem(position)));
                        //tv.setText(getItem(position));

                        return row;
                    }

                };
        lv.setAdapter(adapter);

        alert.show();

答案 2 :(得分：-1)

我认为问题出在inflater上，

final View convertView2 = (View) inflater.inflate(R.layout.costumdialog, null);

您正在投射不需要的视图。

尝试这样的事情

protected Dialog onCreateDialog() {
        LayoutInflater factory = LayoutInflater.from(this);
        final View textEntryView = factory.inflate(R.layout.alert_dialog_text_entry, null);
        return new AlertDialog.Builder(TicTacToe.this)
            //.setIconAttribute(android.R.attr.alertDialogIcon)
            .setTitle(getTitleText())
            .setView(textEntryView)
            .setPositiveButton("JOIN GAME", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int whichButton) {
                    try
                    {
                        EditText et = (EditText)findViewById(R.id.username_edit);
                            playerName = et.getText().toString();
                    }
                    catch (Exception e)
                    {
                    }
                }
            })
            .create();
    return null;
}
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