Question

我是android studio的新手。现在我正在创建一个基本应用程序，当您单击屏幕上的按钮时递归计数从4减少到0。当我在设计视图中查看我的activity_main.xml时，它会显示我想要的内容，但是当我在我的虚拟设备上运行我的应用程序时，它只显示一个没有任何内容的白色屏幕。我怎样才能解决这个问题？我会在这里粘贴我的代码，几乎所有代码都在activity_main.xml和MainActivity.java中

这是activity_main.xml：

<script src="https://unpkg.com/vue"></script>

<div id="app">
<ul>
   <li v-for="eatCategory in eatCategories">
     <label>
        <input type="checkbox" :value="eatCategory.id" v-model="checkedEatCategories">
        <span class="title">{{eatCategory.title}}</span>
     </label>
   </li>
</ul>
<ul>
  <li v-for="post in posts">
    {{ post.title }}
  </li>
</ul>
</div>

这是我的MainActivity.java

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >``

    <Button
        android:id="@+id/button1"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="@string/button1Contents"
        android:onClick="sendMessage"/>

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button1"
        android:layout_alignBottom="@+id/button1"
        android:layout_toRightOf="@+id/button1"
        android:text="@string/textView1Contents" />

</RelativeLayout>

这是我的strings.xml

public class MainActivity extends Activity {

    private static final String TAG = "OneButtonRecursion";

    public void sendMessage(View view) {
        Button clickedButton = (Button) view;

        if (clickedButton == findViewById(R.id.button1)) {
            TextView cup = (TextView) findViewById(R.id.textView1);
            int handFull = Integer.parseInt(cup.getText().toString());

            if (handFull > 0) {
                cup.setText(handFull + "");
                playNextCup(cup, handFull);
            }
        } else {
        }
    }

    public static void playNextCup(TextView cupIn, int handFullIn) {
        handFullIn--;
        cupIn.setText(handFullIn + "");

        if (handFullIn != 0) {
            playNextCup(cupIn, handFullIn);
            Log.i(TAG, "In recursion " + handFullIn);
        } else {
        }

    }
}

Answer 1

您忘记了Override onCreate() 方法

onCreate() 活动开始时调用。这是大多数初始化应该去的地方：调用setContentView（int）来扩展活动的UI，

您的活动中只需Override onCreate()

public class MainActivity extends AppCompatActivity {


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




    }

}

基本的Android应用程序显示空白的白色屏

1 个答案: