如何从Android中的另一个应用程序启动活动

我想从我的Android应用程序启动已安装的软件包。我认为可以使用意图，但是我没有找到一种方法。有链接，在哪里可以找到信息？

如果您不知道主要活动，则可以使用包名称来启动应用程序。

Intent launchIntent = getPackageManager().getLaunchIntentForPackage("com.package.address");
if (launchIntent != null) { 
    startActivity(launchIntent);//null pointer check in case package name was not found
}

我知道已经回答了，但是这是我实现类似内容的方法：

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);
}

更好的是，这里是方法：

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);
    }
}

删除重复的代码：

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);
}

我找到了解决方案。在应用程序的清单文件中，我找到了包名称：com.package.address和要启动的主要活动的名称：MainActivity以下代码启动了该应用程序：

Intent intent = new Intent(Intent.ACTION_MAIN);
intent.setComponent(new ComponentName("com.package.address","com.package.address.MainActivity"));
startActivity(intent);

// in onCreate method
String appName = "Gmail";
String packageName = "com.google.android.gm";
openApp(context, appName, packageName);

public static void openApp(Context context, String appName, String packageName) {
    if (isAppInstalled(context, packageName))
        if (isAppEnabled(context, packageName))
            context.startActivity(context.getPackageManager().getLaunchIntentForPackage(packageName));
        else Toast.makeText(context, appName + " app is not enabled.", Toast.LENGTH_SHORT).show();
    else Toast.makeText(context, appName + " app is not installed.", Toast.LENGTH_SHORT).show();
}

private static boolean isAppInstalled(Context context, String packageName) {
    PackageManager pm = context.getPackageManager();
    try {
        pm.getPackageInfo(packageName, PackageManager.GET_ACTIVITIES);
        return true;
    } catch (PackageManager.NameNotFoundException ignored) {
    }
    return false;
}

private static boolean isAppEnabled(Context context, String packageName) {
    boolean appStatus = false;
    try {
        ApplicationInfo ai = context.getPackageManager().getApplicationInfo(packageName, 0);
        if (ai != null) {
            appStatus = ai.enabled;
        }
    } catch (PackageManager.NameNotFoundException e) {
        e.printStackTrace();
    }
    return appStatus;
}

这是我的示例，如果有人发现它有用，可以从我的应用程序启动条形码/ QR码扫描仪

Intent intent = new Intent("com.google.zxing.client.android.SCAN");
intent.setPackage("com.google.zxing.client.android");

try 
{
    startActivityForResult(intent, SCAN_REQUEST_CODE);
} 
catch (ActivityNotFoundException e) 
{
    //implement prompt dialog asking user to download the package
    AlertDialog.Builder downloadDialog = new AlertDialog.Builder(this);
    downloadDialog.setTitle(stringTitle);
    downloadDialog.setMessage(stringMessage);
    downloadDialog.setPositiveButton("yes",
            new DialogInterface.OnClickListener() 
            {
                public void onClick(DialogInterface dialogInterface, int i) 
                {
                    Uri uri = Uri.parse("market://search?q=pname:com.google.zxing.client.android");
                    Intent intent = new Intent(Intent.ACTION_VIEW, uri);
                    try
                    {
                        myActivity.this.startActivity(intent);
                    }
                    catch (ActivityNotFoundException e)
                    {
                        Dialogs.this.showAlert("ERROR", "Google Play Market not found!");
                    }
                }
            });
    downloadDialog.setNegativeButton("no",
            new DialogInterface.OnClickListener() 
            {
                public void onClick(DialogInterface dialog, int i) 
                {
                    dialog.dismiss();
                }
            });
    downloadDialog.show();
}

根据评论进行编辑

在某些版本中（如注释中所建议），抛出的异常可能有所不同。

因此，下面的解决方案略有修改

Intent launchIntent = null;
try{
   launchIntent = getPackageManager().getLaunchIntentForPackage("applicationId");
} catch (Exception ignored) {}

if(launchIntent == null){
    startActivity(new Intent(Intent.ACTION_VIEW).setData(Uri.parse("https://play.google.com/store/apps/details?id=" + "applicationId")));
} else {
    startActivity(launchIntent);
}

原始答案

尽管回答得很好，但是有一个非常简单的实现可以处理是否未安装该应用程序。我这样做

try{
    startActivity(getPackageManager().getLaunchIntentForPackage("applicationId"));
} catch (PackageManager.NameNotFoundException e) {
    startActivity(new Intent(Intent.ACTION_VIEW).setData(Uri.parse("https://play.google.com/store/apps/details?id=" + "applicationId")));
}

用您要打开的包（例如com.google.maps等）替换“ applicationId”。

// check for the app if it exist in the phone it will lunch it otherwise, it will search for the app in google play app in the phone and to avoid any crash, if no google play app installed in the phone, it will search for the app in the google play store using the browser : 

 public void onLunchAnotherApp() {

        final String appPackageName = getApplicationContext().getPackageName();

        Intent intent = getPackageManager().getLaunchIntentForPackage(appPackageName);
        if (intent != null) {

            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);

        } else {

            onGoToAnotherInAppStore(intent, appPackageName);

        }

    }

    public void onGoToAnotherInAppStore(Intent intent, String appPackageName) {

        try {

            intent = new Intent(Intent.ACTION_VIEW);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.setData(Uri.parse("market://details?id=" + appPackageName));
            startActivity(intent);

        } catch (android.content.ActivityNotFoundException anfe) {

            intent = new Intent(Intent.ACTION_VIEW);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.setData(Uri.parse("http://play.google.com/store/apps/details?id=" + appPackageName));
            startActivity(intent);

        }

    }

如果您想打开另一个应用程序的特定活动，我们可以使用它。

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()
}

如果您需要其他应用程序，则可以显示一个对话框，而不是显示Toast。使用对话框，您可以将用户带到Play-Store下载所需的应用程序。

如果知道数据和已安装的软件包所采取的措施，则只需在启动它之前将这些信息添加到您的intent实例中。

如果您可以访问其他应用程序的AndroidManifest，则可以在其中看到所有需要的信息。

启动新活动的步骤如下：

1.获取包装意向

2.如果intent为null，则将用户重定向到playstore

3.如果intent不为空则打开活动

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);
    }
}

可以Intent.setClassName根据文档使用来启动应用程序的活动。

一个例子：

val activityName = "com.google.android.apps.muzei.MuzeiActivity" // target activity name
val packageName = "net.nurik.roman.muzei" // target package's name
val intent = Intent().setClassName(packageName, activityName)
startActivity(intent)

要在当前应用之外打开它，请在启动意图之前添加此标志。

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)

一个相关的答案在这里

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