效果图

Java 里面有注释了

/**
* Create by JIULANG on 2020
*/
public class MainActivity extends Activity
{
ListView listView;
List<String> listdata= new ArrayList<>();
Button btn ;
EditText et;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
btn = findViewById(R.id.mainButton1);
et = findViewById(R.id.mainEditText1);
btn.setText("查询");
btn.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View p1)
{
String edit = et.getText().toString();
et.setText("");
et.setHint(edit+" :"+getpackageName(edit));
}
});
getAppInfo() ;

et.setHint("应用计数: "+listdata.size() + "个");
final String strdata[] = new String[listdata.size() - 1];//假数据
        for (int i=0;i < listdata.size() - 1;i++)
{
strdata[i] = listdata.get(i) ;
        }
//放个ListView可视化
listView = findViewById(R.id.List1);
//List适配器
ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1, strdata);//新建并配置ArrayAapeter
        listView.setAdapter(adapter);
    }
private String getpackageName(String Name)
{
LinkedHashMap<String,String> map =getAppInfo();
if (map != null)
{
//位置计数
            int index = 0;
            boolean hasContains = false;
//Map遍历
            Object[] keys = map.keySet().toArray();
            for (int i = 0; i < keys.length; i++)
{
                String key = (String) keys[i];
                if (key.equals(Name))
{
                    index = i;
                    hasContains = true;
                    break;
                }
            }
            if (hasContains){

//返回包名
return (String)map.values().toArray()[index];
}
}
return "该应用不存在！";
}
private LinkedHashMap<String,String> getAppInfo()
{
//Map
LinkedHashMap<String,String> packagesmap = new LinkedHashMap<>();

//包管理器
PackageManager  pm = this.getPackageManager();
        List<PackageInfo> piList = pm.getInstalledPackages(PackageManager.GET_ACTIVITIES |
  PackageManager.GET_CONFIGURATIONS |
  PackageManager.GET_GIDS |
  PackageManager.GET_INSTRUMENTATION |
  PackageManager.GET_INTENT_FILTERS |
  PackageManager.GET_META_DATA |
  PackageManager.GET_PERMISSIONS |
  PackageManager.GET_PROVIDERS |
  PackageManager.GET_RECEIVERS |
  PackageManager.GET_SERVICES |
  PackageManager.GET_SHARED_LIBRARY_FILES |
  PackageManager.GET_SIGNATURES |
  PackageManager.GET_URI_PERMISSION_PATTERNS);
        if (piList != null)
{
            for (PackageInfo pi : piList)
{
listdata.add("程序名: " + pi.applicationInfo.loadLabel(pm).toString()+"\n" + "包名:" + pi.packageName +"\n"+ "包共享user id" + pi.sharedUserId);
//Map插入
                packagesmap.put(pi.applicationInfo.loadLabel(pm).toString(),/*包名*/pi.packageName);
}
}
return packagesmap;
}
}

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="match_parent"
android:gravity="center"
android:orientation="vertical">
<EditText
android:layout_width="wrap_content"
android:ems="10"
android:layout_height="wrap_content"
android:id="@+id/mainEditText1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/mainButton1"/>
<ListView
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:id="@+id/List1"/>
</LinearLayout><?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:gravity="center"
android:orientation="vertical">
<EditText
android:layout_width="wrap_content"
android:ems="10"
android:layout_height="wrap_content"
android:id="@+id/mainEditText1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/mainButton1"/>
<ListView
android:layout_width="wrap_content"