为什么我的模拟器上没有显示列表视图？

Question

我正在制作简单的治疗列表视图，但该列表未显示在模拟器上。我已将我的 api 从 22 升级和降级到 30，并将相对布局更改为线性布局，但列表仍未显示。

activty_stress.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="9"
android:background="#83BCD4"
tools:context=".stress">

<TextView
    android:id="@+id/textView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:text="Find your relaxation"
    android:textColor="@color/white"
    android:textSize="18pt" />

<ListView
    android:id="@+id/listview"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="70dp"/>

 </RelativeLayout>

stress.java

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

    ListView listView = findViewById(R.id.listview);

    List<String> list = new ArrayList<>();
    list.add("Therapy1");
    list.add("Therapy2");
    list.add("Therapy3");
    list.add("Therapy4");
    list.add("Therapy5");

    ArrayAdapter arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1,list);
    listView.setAdapter(arrayAdapter);
    
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if (position==0){
                //clicked therapy1
                startActivity(new Intent(stress.this,Therapy1.class));
            } else if (position==1){
                //clicked therapy2
            }else{

            }
        }
    });
}

Answer 1

嘿，试试用LinearLayout替换你的RelativeLayout，或者删除weightSum，因为weightSum不能和RelativeLayout一起使用

Answer 2

用此代码替换。

注意：无论何时给出 textSize，都以 sp 而不是 Pixel 的形式给出。

activty_stress.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#83BCD4"
    android:orientation="vertical">

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:text="Find your relaxation"
        android:textColor="@color/white"
        android:textSize="30sp" />

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="70dp" />

</RelativeLayout>

压力.java

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

        ListView listView = findViewById(R.id.listview);

        List<String> list = new ArrayList<>();
        list.add("Therapy1");
        list.add("Therapy2");
        list.add("Therapy3");
        list.add("Therapy4");
        list.add("Therapy5");

        ArrayAdapter arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, list);
        listView.setAdapter(arrayAdapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if (position == 0) {
                    //clicked therapy1
//                    startActivity(new Intent(stress.this,Therapy1.class));
                } else if (position == 1) {
                    //clicked therapy2
                } else {

                }
            }
        });

    }

输出：