Android(安卓)ListView+ArrayAdapter简单用法

ListView+ArrayAdapter可以几行代码实现一个简单的列表，不用再写一个复杂的继承BaseAdapter的Adapter

最简单的示例

直接用android自带的item布局，几行代码搞定

<?xml version="1.0" encoding="utf-8"?>

public class MainActivity3 extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main3);        final ListView listView = findViewById(R.id.list_view);        String[] items = new String[100];        for (int i = 0; i < items.length; i++) {            items[i] = "item" + i;        }        listView.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, items));    }}

List数据源

上面示例的数据源为数组，ArrayAdapter也支持List数据源

public class MainActivity3 extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main3);        final ListView listView = findViewById(R.id.list_view);        List items = new ArrayList<>();        for (int i = 0; i < 100; i++) {            items.add("item" + i);        }        listView.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, items));    }}

支持自定义对象

上面的数据都是String类型，其实ArrayList也支持自定义的数据类型，显示的内容是改对象toString的内容，所有可以重写对象的toString()方法显示要显示的内容

public class MainActivity3 extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main3);        final ListView listView = findViewById(R.id.list_view);        List items = new ArrayList<>();        for (int i = 0; i < 100; i++) {            items.add(new Student("Student" + i, i));        }        listView.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, items));    }    private class Student {        public String name;        public int age;        public Student() {}        public Student(String name, int age) {            this.name = name;            this.age = age;        }        @Override        public String toString() {            return name + "今年" + age + "岁啦";        }    }}

支持自定义Layout

我们上面item的布局用的是android自带的布局android.R.layout.simple_list_item_1，其实我们也可以自定义布局

先看下android.R.layout.simple_list_item_1的源码

<?xml version="1.0" encoding="utf-8"?>

然后模仿android.R.layout.simple_list_item_1的布局文件，自定义一个布局文件item.xml

这种只有一个TextView的情况下可以不设置TextView的id

<?xml version="1.0" encoding="utf-8"?>

然后在在创建ArrayAdapter时传入R.layout.item即可

listView.setAdapter(new ArrayAdapter<>(this, R.layout.item, items));

需要注意的是如果是如果是一个复杂的布局，一定要指定一个android:id="@android:id/text1"的TextView来显示数据内容，否则ArrayList会默认把最外层的控件转化成TextView，导致类型转化错误，会报如下错误

2019-09-04 15:10:42.838 3838-3838/com.him.hisapp E/ArrayAdapter: You must supply a resource ID for a TextView        --------- beginning of crash2019-09-04 15:10:42.843 3838-3838/com.him.hisapp E/AndroidRuntime: FATAL EXCEPTION: main    Process: com.him.hisapp, PID: 3838    java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView        at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:401)        at android.widget.ArrayAdapter.getView(ArrayAdapter.java:371)        at android.widget.AbsListView.obtainView(AbsListView.java:2413)        at android.widget.ListView.makeAndAddView(ListView.java:1986)        at android.widget.ListView.fillDown(ListView.java:709)        at android.widget.ListView.fillFromTop(ListView.java:770)        at android.widget.ListView.layoutChildren(ListView.java:1749)        at android.widget.AbsListView.onLayout(AbsListView.java:2212)        at android.view.View.layout(View.java:17708)        at android.view.ViewGroup.layout(ViewGroup.java:5631)        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1766)        at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1755)        at android.widget.LinearLayout.onLayout(LinearLayout.java:1521)        at android.view.View.layout(View.java:17708)        at android.view.ViewGroup.layout(ViewGroup.java:5631)        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)        at android.view.View.layout(View.java:17708)        at android.view.ViewGroup.layout(ViewGroup.java:5631)        at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:444)        at android.view.View.layout(View.java:17708)        at android.view.ViewGroup.layout(ViewGroup.java:5631)        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)        at android.view.View.layout(View.java:17708)        at android.view.ViewGroup.layout(ViewGroup.java:5631)        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1766)        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1610)        at android.widget.LinearLayout.onLayout(LinearLayout.java:1519)        at android.view.View.layout(View.java:17708)        at android.view.ViewGroup.layout(ViewGroup.java:5631)        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)        at com.android.internal.policy.DecorView.onLayout(DecorView.java:774)        at android.view.View.layout(View.java:17708)        at android.view.ViewGroup.layout(ViewGroup.java:5631)        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2519)        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2234)        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1372)        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6782)        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:933)        at android.view.Choreographer.doCallbacks(Choreographer.java:742)        at android.view.Choreographer.doFrame(Choreographer.java:674)        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:919)        at android.os.Handler.handleCallback(Handler.java:761)        at android.os.Handler.dispatchMessage(Handler.java:98)        at android.os.Looper.loop(Looper.java:156)        at android.app.ActivityThread.main(ActivityThread.java:6623)        at java.lang.reflect.Method.invoke(Native Method)        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:942)        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:832)     Caused by: java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.TextView        at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:388)        at android.widget.ArrayAdapter.getView(ArrayAdapter.java:371)         at android.widget.AbsListView.obtainView(AbsListView.java:2413)         at android.widget.ListView.makeAndAddView(ListView.java:1986)         at android.widget.ListView.fillDown(ListView.java:709)         at android.widget.ListView.fillFromTop(ListView.java:770)         at android.widget.ListView.layoutChildren(ListView.java:1749)         at android.widget.AbsListView.onLayout(AbsListView.java:2212)         at android.view.View.layout(View.java:17708)         at android.view.ViewGroup.layout(ViewGroup.java:5631)         at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1766)         at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1755)         at android.widget.LinearLayout.onLayout(LinearLayout.java:1521)         at android.view.View.layout(View.java:17708)         at android.view.ViewGroup.layout(ViewGroup.java:5631)         at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)         at android.widget.FrameLayout.onLayout(FrameLayout.java:261)         at android.view.View.layout(View.java:17708)         at android.view.ViewGroup.layout(ViewGroup.java:5631)         at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:444)         at android.view.View.layout(View.java:17708)         at android.view.ViewGroup.layout(ViewGroup.java:5631)         at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)         at android.widget.FrameLayout.onLayout(FrameLayout.java:261)         at android.view.View.layout(View.java:17708)         at android.view.ViewGroup.layout(ViewGroup.java:5631)         at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1766)         at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1610)         at android.widget.LinearLayout.onLayout(LinearLayout.java:1519)         at android.view.View.layout(View.java:17708)         at android.view.ViewGroup.layout(ViewGroup.java:5631)         at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)         at android.widget.FrameLayout.onLayout(FrameLayout.java:261)         at com.android.internal.policy.DecorView.onLayout(DecorView.java:774)         at android.view.View.layout(View.java:17708)         at android.view.ViewGroup.layout(ViewGroup.java:5631)         at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2519)         at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2234)         at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1372)         at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6782)         at android.view.Choreographer$CallbackRecord.run(Choreographer.java:933)         at android.view.Choreographer.doCallbacks(Choreographer.java:742)         at android.view.Choreographer.doFrame(Choreographer.java:674)         at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:919)         at android.os.Handler.handleCallback(Handler.java:761)         at android.os.Handler.dispatchMessage(Handler.java:98)         at android.os.Looper.loop(Looper.java:156)         at android.app.ActivityThread.main(ActivityThread.java:6623)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:942)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:832)

最简单的示例

List数据源

支持自定义对象

支持自定义Layout

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