android - 尝试通过循环动态添加多个 TextView 时应用程序崩溃。添加单个 TextView 时效果很好

Question

当我尝试通过以下代码动态添加多个 TextView 时，Numbers Activity 崩溃了。但是当我不使用循环而只是添加 TextView 时它工作正常。

Numbers Activity.java

    public class NumbersActivity extends AppCompatActivity{

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

        ArrayList<String> words = new ArrayList<String>();
        words.add("one");
        words.add("two");
        words.add("three");
        words.add("four");
        words.add("five");
        words.add("six");
        words.add("seven");
        words.add("eight");
        words.add("nine");
        words.add("ten");

        LinearLayout rootView = (LinearLayout) findViewById(R.id.rootView);
        rootView.removeAllViews();
        TextView  wordView = new TextView((this));
        int index;
        for(index=0; index<words.size(); index++ ){
            wordView.setText(words.get(index));
            rootView.addView(wordView);

        }
    }
}

activity_numbers.xml

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rootView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="16dp"
    android:orientation="vertical"
    tools:context=".NumbersActivity"
</LinearLayout>

我得到的错误是在应用程序崩溃之后

E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.yusuf.miwok, PID: 12226 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.yusuf.miwok/com.example.yusuf.miwok.NumbersActivity}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3194) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3302) at android.app.ActivityThread.-wrap12(Unknown Source:0) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1891) at android.os.Handler.dispatchMessage(Handler.java:108) at android.os.Looper.loop(Looper.java:166) at android.app.ActivityThread.main(ActivityThread.java:7425) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921) Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first. at android.view.ViewGroup.addViewInner(ViewGroup.java:4976) at android.view.ViewGroup.addView(ViewGroup.java:4807) at android.view.ViewGroup.addView(ViewGroup.java:4747) at android.view.ViewGroup.addView(ViewGroup.java:4720) at com.example.yusuf.miwok.NumbersActivity.onCreate(NumbersActivity.java:40) at android.app.Activity.performCreate(Activity.java:7372) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1218) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3147) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3302)  at android.app.ActivityThread.-wrap12(Unknown Source:0)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1891)  at android.os.Handler.dispatchMessage(Handler.java:108)  at android.os.Looper.loop(Looper.java:166)  at android.app.ActivityThread.main(ActivityThread.java:7425)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)  I/Process: Sending signal. PID: 12226 SIG: 9 Application terminated.

Answer 1

正确的代码如下

 public class NumbersActivity extends AppCompatActivity{

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

        ArrayList<String> words = new ArrayList<String>();
        words.add("one");
        words.add("two");
        words.add("three");
        words.add("four");
        words.add("five");
        words.add("six");
        words.add("seven");
        words.add("eight");
        words.add("nine");
        words.add("ten");

        LinearLayout rootView = (LinearLayout) findViewById(R.id.rootView);
        rootView.removeAllViews();

        int index;
        for(index=0; index<words.size(); index++ ){
            TextView  wordView = new TextView((this));
            wordView.setText(words.get(index));
            rootView.addView(wordView);

        }
    }
}

请注意，我只是将这一行移到了 for 循环中

TextView  wordView = new TextView((this));