由于kotlin现在变得非常流行，我认为在kotlin中也提供一个简单的解决方案是合适的。

var launchIntent: Intent? = null
try {
    launchIntent = packageManager.getLaunchIntentForPackage("applicationId")
} catch (ignored: Exception) {
}
if (launchIntent == null) {
    startActivity(Intent(Intent.ACTION_VIEW).setData(Uri.parse("https://play.google.com/store/apps/details?id=" + "applicationId")))
} else {
    startActivity(launchIntent)
}

启动新活动的步骤如下:

1.获取包的意图

2.如果意图为空重定向用户到播放商店

3.如果意图不为空，打开活动

public void launchNewActivity(Context context, String packageName) {
    Intent intent = null;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.CUPCAKE) {
        intent = context.getPackageManager().getLaunchIntentForPackage(packageName);
    }
    if (intent == null) {
        try {
            intent = new Intent(Intent.ACTION_VIEW);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.setData(Uri.parse("market://details?id=" + packageName));
            context.startActivity(intent);
        } catch (android.content.ActivityNotFoundException anfe) {
            startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=" + packageName)));
        }
    } else {
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(intent);
    }
}

private fun openOtherApp() {
        val sendIntent = packageManager.getLaunchIntentForPackage("org.mab.dhyanaqrscanner")
        startActivity(sendIntent)
        finishAffinity()
    }

从API 30 (Android 11)开始，你可以通过launchIntentForPackage接收nullpointerexception

val launchIntent: Intent? = activity.packageManager.getLaunchIntentForPackage("com.google.android.gm")
startActivity(launchIntent) 

为了避免这种情况，您需要将所需的包添加到清单中

<queries>
    <package android:name="com.google.android.gm" />
</queries>

这里是文档 https://developer.android.com/training/package-visibility

而媒体文章 https://medium.com/androiddevelopers/package-visibility-in-android-11-cc857f221cd9

如果你想打开另一个应用程序的特定活动，我们可以使用这个。

Intent intent = new Intent(Intent.ACTION_MAIN, null);
intent.addCategory(Intent.CATEGORY_LAUNCHER);
final ComponentName cn = new ComponentName("com.android.settings", "com.android.settings.fuelgauge.PowerUsageSummary");
intent.setComponent(cn);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
try 
{
    startActivity(intent)
}catch(ActivityNotFoundException e){
    Toast.makeText(context,"Activity Not Found",Toast.LENGTH_SHORT).show()
}

如果你必须需要其他应用程序，你可以显示一个对话框，而不是显示Toast。使用对话框，你可以把用户带到Play-Store下载所需的应用程序。

我知道这个问题已经得到了回答，但以下是我如何实现类似的东西:

Intent intent = getPackageManager().getLaunchIntentForPackage("com.package.name");
if (intent != null) {
    // We found the activity now start the activity
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(intent);
} else {
    // Bring user to the market or let them choose an app?
    intent = new Intent(Intent.ACTION_VIEW);
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    intent.setData(Uri.parse("market://details?id=" + "com.package.name"));
    startActivity(intent);
}

更好的方法是:

public void startNewActivity(Context context, String packageName) {
    Intent intent = context.getPackageManager().getLaunchIntentForPackage(packageName);
    if (intent != null) {
        // We found the activity now start the activity
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(intent);
    } else {
        // Bring user to the market or let them choose an app?
        intent = new Intent(Intent.ACTION_VIEW);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent.setData(Uri.parse("market://details?id=" + packageName));
        context.startActivity(intent);
    }
}

删除重复代码:

public void startNewActivity(Context context, String packageName) {
    Intent intent = context.getPackageManager().getLaunchIntentForPackage(packageName);
    if (intent == null) {
        // Bring user to the market or let them choose an app?
        intent = new Intent(Intent.ACTION_VIEW);
        intent.setData(Uri.parse("market://details?id=" + packageName));
    }
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(intent);
}