android app 中 打开 另一个 app

package com.example.myapplication;

import android.content.ComponentName;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Bundle;

import com.google.android.material.snackbar.Snackbar;

import androidx.appcompat.app.AppCompatActivity;

import android.view.View;

import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;

import com.example.myapplication.databinding.ActivityMainBinding;

import android.view.Menu;
import android.view.MenuItem;

import java.util.List;

public class MainActivity extends AppCompatActivity {
    
    

    private AppBarConfiguration appBarConfiguration;
    private ActivityMainBinding binding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);

        binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        setSupportActionBar(binding.toolbar);

        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
        appBarConfiguration = new AppBarConfiguration.Builder(navController.getGraph()).build();
        NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);

        binding.fab.setOnClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
                doStartApplicationWithPackageName("com.termux");
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
    
    
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
    
    
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
    
    
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public boolean onSupportNavigateUp() {
    
    
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
        return NavigationUI.navigateUp(navController, appBarConfiguration)
                || super.onSupportNavigateUp();
    }

    private void doStartApplicationWithPackageName(String packagename) {
    
    

        // 通过包名获取此APP详细信息，包括Activities、services、versioncode、name等等
        PackageInfo packageinfo = null;
        try {
    
    
            packageinfo = getPackageManager().getPackageInfo(packagename, 0);
        } catch (PackageManager.NameNotFoundException e) {
    
    
            e.printStackTrace();
        }
        if (packageinfo == null) {
    
    
            return;
        }

        // 创建一个类别为CATEGORY_LAUNCHER的该包名的Intent
        Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null);
        resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        resolveIntent.setPackage(packageinfo.packageName);

        // 通过getPackageManager()的queryIntentActivities方法遍历
        List<ResolveInfo> resolveinfoList = getPackageManager()
                .queryIntentActivities(resolveIntent, 0);

        ResolveInfo resolveinfo = resolveinfoList.iterator().next();
        if (resolveinfo != null) {
    
    
            // packagename = 参数packname
            String packageName = resolveinfo.activityInfo.packageName;
            // 这个就是我们要找的该APP的LAUNCHER的Activity[组织形式：packagename.mainActivityname]
            String className = resolveinfo.activityInfo.name;
            // LAUNCHER Intent
            Intent intent = new Intent(Intent.ACTION_MAIN);
            intent.addCategory(Intent.CATEGORY_LAUNCHER);

            // 设置ComponentName参数1:packagename参数2:MainActivity路径
            ComponentName cn = new ComponentName(packageName, className);

            intent.setComponent(cn);
            startActivity(intent);
        }
    }
}

查看 以上代码中 打开 app方法：

 doStartApplicationWithPackageName("com.termux");

具体方法实现：

 private void doStartApplicationWithPackageName(String packagename) {
    
    

        // 通过包名获取此APP详细信息，包括Activities、services、versioncode、name等等
        PackageInfo packageinfo = null;
        try {
    
    
            packageinfo = getPackageManager().getPackageInfo(packagename, 0);
        } catch (PackageManager.NameNotFoundException e) {
    
    
            e.printStackTrace();
        }
        if (packageinfo == null) {
    
    
            return;
        }

        // 创建一个类别为CATEGORY_LAUNCHER的该包名的Intent
        Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null);
        resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        resolveIntent.setPackage(packageinfo.packageName);

        // 通过getPackageManager()的queryIntentActivities方法遍历
        List<ResolveInfo> resolveinfoList = getPackageManager()
                .queryIntentActivities(resolveIntent, 0);

        ResolveInfo resolveinfo = resolveinfoList.iterator().next();
        if (resolveinfo != null) {
    
    
            // packagename = 参数packname
            String packageName = resolveinfo.activityInfo.packageName;
            // 这个就是我们要找的该APP的LAUNCHER的Activity[组织形式：packagename.mainActivityname]
            String className = resolveinfo.activityInfo.name;
            // LAUNCHER Intent
            Intent intent = new Intent(Intent.ACTION_MAIN);
            intent.addCategory(Intent.CATEGORY_LAUNCHER);

            // 设置ComponentName参数1:packagename参数2:MainActivity路径
            ComponentName cn = new ComponentName(packageName, className);

            intent.setComponent(cn);
            startActivity(intent);
        }
    }