How to set a TextView from an ArrayList, character by character, sequentially?

Question

I want to put a text in a TextView sequentially, with a known time between characters, from a written text in an EditText

That is the solution I made: I wrote two ArrayList charged from an EditText, the first one with Characters from the EditText , the second one with Integers for determine the time between characters. Then I parse the ArrayLists, times load of the time integers are done sequentially, but not the characters, the TextViews are drawn only when the cycle ends.

My code The MainActivity:

import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
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 TextView showCharacter;
private TextView showAppendCharacter;
private EditText incomingText;
private Button readTextEdit;

private ArrayList<CharSequence> toText = new ArrayList<CharSequence>();
private ArrayList<Integer> timePlay = new ArrayList<Integer>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    showCharacter = (TextView) findViewById(R.id.showCharacterTextView);
    showAppendCharacter = (TextView) findViewById(R.id.showAppendCharacterTextView);
    incomingText = (EditText) findViewById(R.id.incomingEditText);
    readTextEdit = (Button) findViewById(R.id.readTextButton);

    readTextEdit.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            toText.clear();
            timePlay.clear();
            showAppendCharacter.setText("");

            String text = incomingText.getText().toString();
            for (int base = 0; base < text.length(); base++) {
                if (String.valueOf(text.charAt(base)).equals("a")) {
                    toText.add(("a"));
                    timePlay.add(500);
                } else if (String.valueOf(text.charAt(base)).equals("b")) {
                    toText.add(("b"));
                    timePlay.add(650);
                } else if (String.valueOf(text.charAt(base)).equals("c")) {
                    toText.add(("c"));
                    timePlay.add(800);
                } else {
                    toText.add(("_"));
                    timePlay.add(1000);
                }
            }

            for (int pos = 0; pos < toText.size(); pos++) {
                try {
                    Thread.sleep(timePlay.get(pos));
                    showCharacter.setText((String) toText.get(pos));
                    showAppendCharacter.append((String) toText.get(pos));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    });
}
}

The activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/showCharacterTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/showCharacterTextView"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<TextView
    android:id="@+id/showAppendCharacterTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/showAppendCharactersTextView"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText
    android:id="@+id/incomingEditText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ems="10"
    android:hint="@string/incomingTextEditText"
    android:inputType="text" >

    <requestFocus />
</EditText>

<Button
    android:id="@+id/readTextButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/readButton" />

The strings.xml:

<?xml version="1.0" encoding="utf-8"?>

<string name="app_name">texto Desde ArrayList</string>
<string name="action_settings">Settings</string>
<string name="showCharacterTextView">Show last Character</string>
<string name="showAppendCharactersTextView">Show append Characters</string>
<string name="incomingTextEditText">Incoming text</string>
<string name="readButton">Read text</string>

Answer 1

Try something like this... You can get rid of the Arraylists. Remember a String is basically an array of chars. create a custom text view that implements runnable so the work that your trying to do with the text is not done on the main thread.

package com.example.stackquestion;

import java.util.ArrayList;

import android.content.Context;
import android.graphics.Color;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.widget.TextView;

public class CustomTextView extends TextView implements Runnable {
    String  text        = null;
    int     i           = 0;
    int     length      = 0;
    String  currentText = "";

    public CustomTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        reset();
    }

    @Override
    public void run() {

        if (i < length) {
            currentText = currentText + text.charAt(i);
            setText(currentText);
            if (text.charAt(i) == 'a') {
                postDelayed(this, 500);
            } else if (text.charAt(i) == 'b') {
                postDelayed(this, 650);
            } else if (text.charAt(i) == 'c') {
                postDelayed(this, 800);
            } else if (text.charAt(i) == '_') {
                postDelayed(this, 1000);
            } else
                postDelayed(this, 1);
            i++;
        }
    }

    public void setString(String text) {
        this.text = text;
        this.length = text.length();
    }

    public void reset() {
        currentText = "";
        text = null;
        i = 0;
        setText("");
    }
}

Here is the main Activity

package com.example.stackquestion;

import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
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 TextView                showCharacter;
    private CustomTextView          showAppendCharacter;
    private EditText                incomingText;
    private Button                  readTextEdit;

    private ArrayList<CharSequence> toText      = new ArrayList<CharSequence>();
    private ArrayList<Integer>      timePlay    = new ArrayList<Integer>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        showCharacter = (TextView) findViewById(R.id.showCharacterTextView);
        showAppendCharacter = (CustomTextView) findViewById(R.id.showAppendCharacterTextView);
        incomingText = (EditText) findViewById(R.id.incomingEditText);
        readTextEdit = (Button) findViewById(R.id.readTextButton);

        readTextEdit.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (v.getId() == R.id.readTextButton)
                    showAppendCharacter.reset();
                showAppendCharacter
                        .setString(incomingText.getText().toString());
                showAppendCharacter.run();
            }
        });
    }
}

woops. I forgot to give you the Layout. But looks like you got it. Just change the type of textview to a fully qualified CustomTextView. Here was mine.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/showCharacterTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/showCharacterTextView"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <com.example.stackquestion.CustomTextView
        android:id="@+id/showAppendCharacterTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/showAppendCharactersTextView"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/incomingEditText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="@string/incomingTextEditText"
        android:inputType="text" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/readTextButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/readButton" />

</LinearLayout>