Android学习-列表视图ListView _android学习

【Android学习-列表视图ListView】落花踏尽游何处，笑入胡姬酒肆中。这篇文章主要讲述Android学习-列表视图ListView相关的知识，希望能为你提供帮助。
一、简介：ListView，列表视图，直接继承了AbsListView，是一个以垂直方式在项目中显示View视图的列表。ListView的数据项，来自一个继承了ListAdapter接口的适配器。

二、新建一个包listview并新建ListViewActivity.java活动：

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public class ListViewActivity extends AppCompatActivity {

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

三、在androidManifest.xml中声名activity：

1	< activity android:name=".listview.ListViewActivity"> < /activity>

四、建立activity_list_view.xml布局：

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< ?xml version="1.0" encoding="utf-8"?>
< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

< /LinearLayout>

五、在activity_main.xml中新建一个按钮：

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< Button
android:id="@+id/btn_listview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="ListView"
android:textAllCaps="false"/>

六、在MainActivity.java中声名控件：

1	private Button mBtnListView;

七、在MainActivity.java中找到控件：

1	mBtnListView=findViewById(R.id.btn_listview);

八、设置点击事件：

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mBtnListView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//跳转到ListView演示页面
Intent intent=new Intent(MainActivity.this,ListViewActivity.class);
startActivity(intent);
}
});

九、在activity_list_view.xml布局中写代码：

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< ?xml version="1.0" encoding="utf-8"?>
< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

< ListView
android:id="@+id/lv_1"
android:layout_width="match_parent"
android:layout_height="wrap_content">

< /ListView>
< /LinearLayout>

十、新建layout_list_item.xml:

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< ?xml version="1.0" encoding="utf-8"?>
< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:paddingTop="10dp"
android:paddingBottom="10dp">

< ImageView
android:id="@+id/iv"
android:layout_width="100dp"
android:layout_height="100dp"
android:scaleType="centerCrop"
android:background="#000"/>

< LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingLeft="10dp">

< TextView
android:id="@+id/tv_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello"
android:textSize="20sp"
android:textColor="#000"/>

< TextView
android:id="@+id/tv_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="2018-11-27"
android:textSize="18sp"
android:textColor="#808080"
android:layout_marginTop="10dp"/>

< TextView
android:id="@+id/tv_content"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="这是内容"
android:textSize="18sp"
android:textColor="#808080"
android:layout_marginTop="10dp"/>

< /LinearLayout>
< /LinearLayout>

十一、在包listview中新建MyListAdapter.java继承自BaseAdapter:

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public class MyListAdapter extends BaseAdapter {

private Context mContext;
private LayoutInflater mLayoutInflater;

public MyListAdapter(Context context){
this.mContext=context;
mLayoutInflater=LayoutInflater.from(context);
}

@Override
public int getCount() {
return 10;
}

@Override
public Object getItem(int i) {
return null;
}

@Override
public long getItemId(int i) {
return 0;
}

static class ViewHolder{
public ImageView imageView;
public TextView tvTitle,tvTime,tvContent;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder=null;
if(convertView==null){
convertView=mLayoutInflater.inflate(R.layout.layout_list_item,null);
holder=new ViewHolder();
holder.imageView=convertView.findViewById(R.id.iv);
holder.tvTitle=convertView.findViewById(R.id.tv_title);
holder.tvTime=convertView.findViewById(R.id.tv_time);
holder.tvContent=convertView.findViewById(R.id.tv_content);
convertView.setTag(holder);
}else{
holder=(ViewHolder)convertView.getTag();
}
//给控件赋值
holder.tvTitle.setText("这是标题");
holder.tvTime.setText("2018-11-28");
holder.tvContent.setText("这是内容");
Glide.with(mContext).load("https://www.baidu.com/img/bd_logo1.png?where=super").into(holder.imageView);
return convertView;
}
}

十二、在ListViewActivity.java中写代码：

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public class ListViewActivity extends AppCompatActivity {

private ListView mLv1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_view);

mLv1=findViewById(R.id.lv_1);
mLv1.setAdapter(new MyListAdapter(ListViewActivity.this));
}
}

运行结果：

文章图片

十三、在drawable下新建一个list_item:

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< ?xml version="1.0" encoding="utf-8"?>
< selector xmlns:android="http://schemas.android.com/apk/res/android">
< item android:state_selected="true" android:drawable="@color/colorAccent"/>
< item android:state_pressed="true" android:drawable="@color/colorAccent"/>
< item android:state_focused="true" android:drawable="@color/colorAccent"/>
< item android:drawable="@color/colorWhite"/>
< /selector>

十四、在activity_list_view.xml下配置：

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< ?xml version="1.0" encoding="utf-8"?>
< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

< ListView
android:id="@+id/lv_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:listSelector="@drawable/list_item">

< /ListView>
< /LinearLayout>

运行截图：

文章图片

十五、在ListViewActivity.java设置点击和长按事件：

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mLv1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView< ?> adapterView, View view, int position, long l) {
Toast.makeText(ListViewActivity.this,"点击 pos:"+position,Toast.LENGTH_SHORT).show();
}
});

mLv1.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView< ?> adapterView, View view, int position, long l) {
Toast.makeText(ListViewActivity.this,"长按 pos:"+position,Toast.LENGTH_SHORT).show();
return true; //松开后不会显示点击事件
}
});