Android 一个APP打开另一个app的两种方式,需添加QUERY_ALL_PACKAGES权限

加＜uses-permission android:name="android.permission.QUERY_ALL_PACKAGES"/>

方式1：打开外部app，在新窗口打开。
    private void doStartAppPackageName(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;
        }
        Intent resolveIntent = getPackageManager().getLaunchIntentForPackage(packagename);// 包名
        startActivity(resolveIntent);// 启动目标应用
    }

方式2：打开外部app，嵌入旧窗口中。 

    private void doStartAppPackageName(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) {
            String packageName = resolveinfo.activityInfo.packageName;
            String className = resolveinfo.activityInfo.name;

            Intent intent = new Intent(Intent.ACTION_MAIN);
            intent.addCategory(Intent.CATEGORY_LAUNCHER);
            ComponentName cn = new ComponentName(packageName, className);
            intent.setComponent(cn);
            startActivity(intent);
        }
    }