英文:
How to display item and subitem from HashMap in ListView
问题
我想要从HashMap中显示项目和子项目，项目将是字符串（借款人姓名），子项目为双精度（借款人贷款）。这是我的第一个Android应用程序，所以请理解：）
这是我的布局：
<?xml version="1.0" encoding="utf-8"?>
<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:gravity="center"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="669dp">
</ListView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<Button
android:id="@+id/editButton"
android:layout_width="244dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Dodaj" />
<Button
android:id="@+id/sumButton"
android:layout_width="202dp"
android:layout_height="wrap_content"
android:text="Suma dlugow" />
</LinearLayout>
</LinearLayout>
</RelativeLayout>
后端代码：
listView = findViewById(R.id.listView);
Map<String, Double> borrowers = new HashMap<>();
ArrayList<String> arrayList = new ArrayList<>();
borrowers.put("John", 300.0);
arrayList.add(String.valueOf(borrowers));
ArrayAdapter<Borrower> arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, arrayList);
listView.setAdapter(arrayAdapter);
应用程序仅显示一个项目，它看起来像 {John=300.0}，我希望它看起来像：
John
300.0
或者只是
John 300
英文:
I would like to display item and subitem from HashMap, item would be String (borrower name), subitem double(borrower loan). It's my first android app so be understanding 
It's my layout
<?xml version="1.0" encoding="utf-8"?>
<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:gravity="center"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="669dp">
</ListView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<Button
android:id="@+id/editButton"
android:layout_width="244dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Dodaj" />
<Button
android:id="@+id/sumButton"
android:layout_width="202dp"
android:layout_height="wrap_content"
android:text="Suma dlugow" />
</LinearLayout>
</LinearLayout>
</RelativeLayout>
And backend
listView = findViewById(R.id.listView);
Map<String, Double> borrowers = new HashMap<>();
ArrayList<String> arrayList = new ArrayList<>();
borrowers.put("John", 300.0);
arrayList.add(String.valueOf(borrowers));
ArrayAdapter<Borrower> arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, arrayList);
listView.setAdapter(arrayAdapter);
And app display only one item and it's look like {John=300.0}, i want to look like:
John
300.0
or just John \t 300
答案1
得分: 1
你当前的代码只是获取整个映射的String值。您需要遍历映射以获取键和值，然后构造新的String并将其添加到您的List中。
for (Map.Entry<String, Double> entry : borrowers.entrySet()) {
String key = entry.getKey();
Double value = entry.getValue();
arrayList.add(key + "\t" + value);
}
英文:
Your current code is just grabbing the String value of the entire map. You need to iterate over the map to grab the key and value and then construct your new String and add it to your List.
for (Map.Entry<String, Double> entry : borrowers.entrySet()) {
String key = entry.getKey();
Double value = entry.getValue();
arrayList.add(key + "\t" + value);
}
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