通用的Adapter
2024-08-30 07:42:38
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" > <ListView
android:id="@+id/lv_main_apps"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" >
</ListView>
</LinearLayout>
item_app.xml
<?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="70dp"
android:minHeight="70dp"
android:orientation="horizontal"
android:gravity="center_vertical"> <ImageView
android:id="@+id/iv_item_icon"
android:layout_width="70dp"
android:layout_height="70dp"
android:src="@drawable/ic_launcher" /> <TextView
android:id="@+id/tv_item_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView" /> </LinearLayout>
AppInfo
package com.example.app3_listview;
import android.graphics.drawable.Drawable;
public class AppInfo {
private Drawable icon;
private String appName;
private String packageName;
public AppInfo(Drawable icon, String appName, String packageName) {
super();
this.icon = icon;
this.appName = appName;
this.packageName = packageName;
}
public AppInfo() {
super();
}
public Drawable getIcon() {
return icon;
}
public void setIcon(Drawable icon) {
this.icon = icon;
}
public String getAppName() {
return appName;
}
public void setAppName(String appName) {
this.appName = appName;
}
public String getPackageName() {
return packageName;
}
public void setPackageName(String packageName) {
this.packageName = packageName;
}
@Override
public String toString() {
return "AppInfo [icon=" + icon + ", appName=" + appName
+ ", packageName=" + packageName + "]";
}
}
MainActivity
package com.example.app3_listview; import java.util.ArrayList;
import java.util.List; import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast; import com.example.adapter.base.CommonBaseAdapter;
import com.example.adapter.base.ViewHolder; public class MainActivity extends Activity { private ListView lv_main_apps;
private List<AppInfo> data;
private MyAdapter adapter; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// 载入视图--仅仅有一个listview
setContentView(R.layout.activity_main);
// 获取id
lv_main_apps = (ListView) findViewById(R.id.lv_main_apps); // 得到数据
data = getAllAppInfos(); // 创建adapter
adapter = new MyAdapter(this, data, R.layout.item_app); // 设置adapter显示
lv_main_apps.setAdapter(adapter); // 设置每项(item)的点击监听
lv_main_apps
.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {// position 点击的下标
// 得到数据
AppInfo appInfo = data.get(position);
String appName = appInfo.getAppName();
// 显示
Toast.makeText(MainActivity.this, appName, 0).show();
}
});
} /*
* 得到手机中全部应用信息的列表 AppInfo
*/
protected List<AppInfo> getAllAppInfos() { List<AppInfo> list = new ArrayList<AppInfo>();
// 得到应用的packgeManager
PackageManager packageManager = getPackageManager();
// 创建一个主界面的intent
Intent intent = new Intent();
intent.setAction(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_LAUNCHER);
// 得到包括应用信息的列表
List<ResolveInfo> ResolveInfos = packageManager.queryIntentActivities(
intent, 0);
// 遍历
for (ResolveInfo ri : ResolveInfos) {
// 得到包名
String packageName = ri.activityInfo.packageName;
// 得到图标
Drawable icon = ri.loadIcon(packageManager);
// 得到应用名称
String appName = ri.loadLabel(packageManager).toString();
// 封装应用信息对象
AppInfo appInfo = new AppInfo(icon, appName, packageName);
// 加入到list
list.add(appInfo);
}
return list;
} /**
* 继承自CommonBaseAdapter的adapter类
*/
class MyAdapter extends CommonBaseAdapter<AppInfo> { public MyAdapter(Context context, final List<AppInfo> data, int layoutId) {
super(context, data, layoutId, new Convert() {
@Override
public void convert(ViewHolder holder, int position) { AppInfo appInfo = data.get(position);
holder.setText(R.id.tv_item_name, appInfo.getAppName()).setImageDrawable(R.id.iv_item_icon,appInfo.getIcon());
}
});
} }
}
CommonBaseAdapter
package com.example.adapter.base; import java.util.List; import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter; /**
* 通用的baseAdapter
*/
public abstract class CommonBaseAdapter<T> extends BaseAdapter { private Context context;
private List<T> data;
private int layoutId;
public Convert convert; /**
* 设置视图数据的抽象方法, 由详细的adapter子类来实现
*/
public interface Convert{
void convert(ViewHolder holder, int position);
}
public CommonBaseAdapter(Context context, List<T> data, int layoutId,Convert convert) {
this.context = context;
this.data = data;
this.layoutId = layoutId;
this.convert = convert;
} @Override
public int getCount() {
return data.size();
} @Override
public T getItem(int position) {
return data.get(position);
} @Override
public long getItemId(int position) {
return 0;
} @Override
public View getView(int position, View convertView, ViewGroup parent) {
//得到Viewholder对象
ViewHolder holder = ViewHolder.getHolder(context, convertView,
layoutId);
//调用未实现的抽象方法设置数据
convert.convert(holder, position);
//返回holder中的convertView
return holder.getConvertView();
} }
ViewHolder
package com.example.adapter.base; import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.SparseArray;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView; /**
* 通用的ViewHolder类
*/
public class ViewHolder { // 代表当前行的view对象
private View itemConvertView;
// 用来替代Map<Integer,Object>的容器, 效率比map高
private SparseArray<View> views; /*******************************************************************
* 得到ViewHolder对象 context--layoutId：这个是用来构造时候，须要动态载入布局文件
* convertview:是可复用的item布局
*/
public static ViewHolder getHolder(Context context, View convertView,
int layoutId) {
/**
* 假设没有可复用的布局。就创建本类对象 假设有的话，就通过getTag获取
* */
if (convertView == null) {
return new ViewHolder(context, layoutId);
} else {
ViewHolder holder = (ViewHolder) convertView.getTag();
return holder;
}
} /**
* 构造方法 载入布局文件。将本类标记即viewholder保存到itemConvertView中
*/
private ViewHolder(Context context, int layoutId) {
this.itemConvertView = View.inflate(context, layoutId, null);
this.itemConvertView.setTag(this);
views = new SparseArray<View>();
} /**
* 得到当前相应的convertView
*/
public View getConvertView() {
return itemConvertView;
} /*************************
* %%%%%%%%%%%%******************************** 依据视图id得到相应的视图对象
*/
public <T extends View> T getView(int viewId) {
View view = views.get(viewId);
if (view == null) {
view = itemConvertView.findViewById(viewId);
views.put(viewId, view);
}
return (T) view;
} // /**
* 设置文本数据
*/
public ViewHolder setText(int viewId, String text) {
TextView textView = getView(viewId);
textView.setText(text);
return this;
} /**
* 设置drawable图片
*/
public ViewHolder setImageDrawable(int viewId, Drawable drawable) {
ImageView imageView = getView(viewId);
imageView.setImageDrawable(drawable);
return this;
} /**
* 设置资源图片
*/
public ViewHolder setImageResource(int viewId, int resourceId) {
ImageView imageView = getView(viewId);
imageView.setImageResource(resourceId);
return this;
}
}
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