Use Listview and ListPicker

Now we will try another component from app inventor 2. There are listview and listpicker. Listview is like combo box in J2SE or spinner in app inventor 2. the function of listview is like spinner but it is not open another screen, it just in the same screen. if you want to catch a value from listview, you can get and view that in label. Different with spinner, spinner’s action can make basic interface is lock after the spinner is choose. About listpicker, when listpicker is click, there is a value that can be choosed in listpicker‘s screen. After choosed value, it will return to first listpicker button, and the value will be filled in that listpicker button. Here the example :

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Here the block code :

  1. ListView

  2. ListPicker
    listpickerBlock

    ListPicker Block

    listpickerBlockFinal

    Final Block ListPicker

  3. Slider
    sliderBlock

    Slider Block

    sliderBlockFinal

    Final Slider Block

Try Spinner in app inventor 2

now, in this page… we will talk about spinner. in java dekstop (J2SE), spinner like combo box, the value answer can be choosed. After choose the answer, the value will be catched in the variable of spinner. In the previous page, we talk about if condition, the preview shows a view component especially spinner. so, in this page, we will view again that image to reader and add a new information properties of spinner. here the preview :

Login_first

in the right side of screen1, there is a component’s widget that fill an structure of component and a spinner componen can view a properties if you click the spinner’s component (it shows in properties’s widget). The spinner value can fill in the “ElementsFromString” textfield. The value must be spaced with coma. In “Prompt” fill, it just give an information of spinner like header name of spinner.

spinner

Result in emulator :

spinnerEm

Here the “Block” code :

spinnerBlock

App Inventor 2 : If Condition

if condition usually use to compare two or more answer that are suitable or not. this condition produces an answer true or false value.  for an example :

Login_first

here the example block code for if condition:

login_block

In emulator there is a spinner for choose a status, here the block code combine with if condition :

fixSpin

Model Class System.out.print in Android

In java, if we want to print a value from variable or other process, we can use System.out.print() or System.out.println(). it’s always work in java, but when it try in android program, we can’t find it or System.out.print maybe can’t use in android. Android already give an alternative syntax for handle System.out.print from java, is Log class. Log class is coming from android.util.Log, That’s a reference library for use or take a Log class syntax.

Here an example : 

package com.apps.helloworld;

import android.os.Bundle;
import android.provider.Settings.System;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {

private EditText txtInggris;
private EditText txtIndonesia;
private EditText txtJerman;
public static final String INGGRIS = “Inggris”;
public static final String INDONESIA = “Indonesia”;
public static final String JERMAN = “Jerman”;
private Button btn;
private TextView tv;
AlertDialog al;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

txtInggris = (EditText)findViewById(R.id.FormView);
tv = (TextView)findViewById(R.id.textView1);
btn = (Button)findViewById(R.id.button1);
al = new AlertDialog.Builder(this).create();

btn.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
tv.setText(txtInggris.getText());

al.setMessage(“ok”);
Log.d(“T”, “test”);
Log.i(“T”, “test lg”);
al.setButton(“Ok aja”, new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
al.show();

}
});
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}

So, The result from the code will be showed in LogCat.

Here the result :

Result LogCat

Result LogCat