在TextView上执行setText后，Android应用程序崩溃 [英] Android app crash after setText on a TextView

问题描述

我正在尝试以编程方式设置 TextView 的文本.在我的应用程序中，我正在调用一个方法，该方法创建一个内部带有 View 的 TableRow .此 View 包含一个 TextView .现在，我正在尝试使用 setText()方法更改Text.

I'm trying to set the text of a TextView programmatically. In my app I'm calling a method which creates a TableRow with aView inside. This View contains a TextView. And now I'm trying to change the Text with the method setText().

city_layout.xml

city_layout.xml

...
 <TextView
        android:id="@+id/textView_City_Name"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/city_name"
        android:textColor="#FFFFFF"
        android:textSize="35dp"
        android:gravity="center_horizontal"
        android:textStyle="bold"
        android:paddingTop="65dp"/>
...

和我的片段类

private View createCityInList(String cityName) {
    TableRow tr = new TableRow(getActivity());
    View v = LayoutInflater.from(getActivity()).inflate(R.layout.city_layout, tr, false);

    //change attr here!
    TextView textView = (TextView) getView().findViewById(R.id.textView_City_Name);
    textView.setText(cityName);
    return v;
}

因此，如果我尝试在手机上运行该应用程序，则该应用程序刚刚关闭，logcat给了我

So if I try to run this on my phone the app just closed and logcat give me this

java.lang.RuntimeException: Unable to start activity ComponentInfo{de.app.city/de.app.city.MainActivity}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2338)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
        at android.app.ActivityThread.access$800(ActivityThread.java:151)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
        at android.os.Handler.dispatchMessage(Handler.java:110)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:5292)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException

我不知道setText行有什么问题，有人可以告诉我吗?

I don't know what's wrong with the setText line, can someone tell me?

可能有帮助:在我的片段中，我指向了另一个布局(fragment_layout).但是我想创建一个city_layout视图并更改textview中的文本.我要在fragment_layout中显示此视图.

Maybe helpful: In my fragment I'm pointing on another layout (fragment_layout). But I want to create a View of city_layout and change the text in the textview. This view I want to display in fragment_layout.

推荐答案

这是您的问题

private View createCityInList(String cityName) {
    TableRow tr = new TableRow(getActivity());
    View v = LayoutInflater.from(getActivity()).inflate(R.layout.city_layout, tr, false);

    //change attr here!
    TextView textView = (TextView) getView().findViewById(R.id.textView_City_Name);
    textView.setText(cityName);
    return v;
}

getView()在这里为空.

getView() here is null.

将其更改为:

private View createCityInList(String cityName) {
    TableRow tr = new TableRow(getActivity());
    View v = LayoutInflater.from(getActivity()).inflate(R.layout.city_layout, tr, false);

    //change attr here!
    TextView textView = (TextView) v.findViewById(R.id.textView_City_Name);
    textView.setText(cityName);
    return v;
}

您会全部准备就绪.

这篇关于在TextView上执行setText后，Android应用程序崩溃的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！