在Kotlin

fun openApplicationOrMarket(packageName: String) {
        var intent = requireContext().packageManager.getLaunchIntentForPackage(packageName)
        if (intent == null) {
            intent = Intent(Intent.ACTION_VIEW)
            intent.data = Uri.parse("market://details?id=$packageName")
        }

        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
        requireContext().startActivity(intent)
    }

试试下面的代码:

Intent intent = new Intent(Intent.ACTION_MAIN);
intent.setComponent(new ComponentName("package_name", "Class_name"));
if (intent.resolveActivity(getPackageManager()) != null) 
{
   startActivity(intent);
}

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()
    }

传递包名和你想要显示的消息，如果包没有安装;-)

void openApp(String appPackageName,String message){
    Intent launchIntent = getPackageManager().getLaunchIntentForPackage(appPackageName);
    if (launchIntent != null) {
        startActivity(launchIntent);
    } else {
        Toast.makeText(MainActivity.this, message, Toast.LENGTH_LONG).show();
        startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=" + appPackageName)));
    }
}

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)
}