andriod 获得应用程序名称

import android.annotation.TargetApi;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

public String getApplicationName() {
        PackageManager packageManager = null;
        ApplicationInfo applicationInfo = null;
        try {
            packageManager = getApplicationContext().getPackageManager();
            applicationInfo = packageManager.getApplicationInfo(getPackageName(), 0);
        } catch (PackageManager.NameNotFoundException e) {
            applicationInfo = null;
        }
        String applicationName =
                (String) packageManager.getApplicationLabel(applicationInfo);
        return applicationName;
    }