Android Handler Periodically

Question

This I want I want to achieve:

1. An activity starts with no ClickListener and has four textviews all with white background

2. I want to change th

Answer 1

There is no need to create a thread for this, or animations.

The solution is really simple: use Handler.postDelayed() or Handler.sendMessageDelayed():

http://developer.android.com/reference/android/os/Handler.html#postDelayed(java.lang.Runnable, long) http://developer.android.com/reference/android/os/Handler.html#sendMessageDelayed(android.os.Message, long)

For a robust implementation, be sure to remove any pending messages at least by Activity.onDestroy(). (Or if you are posting them in Activity.onStart(), remove them in Activity.onStop(); if posting in Activity.onResume(), remove in Activity.onPause().)

Answer 2

I have one sample for this task but by thread with handleMessage

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Handler;
import android.widget.EditText;
import android.widget.TextView;

public class l15_threadOneaacto extends Activity  {
    /** Called when the activity is first created. */
    TextView tv[]=new TextView[4];
    EditText et;
    Thread bcko;
    static int index=0;

    boolean isRunning=false;
    boolean acceptevent=false;
    Handler hn=new Handler(){
        @Override
        public void handleMessage(android.os.Message msg) {
            switch (index) {
            case 0: tv[0].setBackgroundColor(Color.BLUE);  break;
            case 1: tv[0].setBackgroundColor(Color.WHITE);  break;
            case 2: tv[1].setBackgroundColor(Color.BLUE);  break;
            case 3: tv[1].setBackgroundColor(Color.WHITE);  break;
            case 4: tv[2].setBackgroundColor(Color.BLUE);  break;
            case 5: tv[2].setBackgroundColor(Color.WHITE);  break;
            case 6: tv[3].setBackgroundColor(Color.BLUE);  break;
            case 7: tv[3].setBackgroundColor(Color.WHITE);  break;
            }
            index++;
            if(index==8){
                acceptevent=true;
                et=(EditText)findViewById(R.id.bbb);
                et.setText("ready for input");
            }

        };

    };


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

        tv[0]=(TextView)findViewById(R.id.tx1);
        tv[1]=(TextView)findViewById(R.id.tx2);
        tv[2]=(TextView)findViewById(R.id.tx3);
        tv[3]=(TextView)findViewById(R.id.tx4);





    }




    @Override
    protected void onStart() {
        // TODO Auto-generated method stub
        super.onStart();

         bcko=new Thread (new Runnable() {

            @Override
            public void run() {
                try {

                        //
                        for(int i=0;i<8 && isRunning;i++){
                            Thread.sleep(2000);
                        hn.sendMessage(hn.obtainMessage());
                        }

                } catch (Exception e) {
                    // TODO: handle exception
                }

            }
        });
        isRunning=true;
        bcko.start();



    }
    @Override
    protected void onStop() {
        // TODO Auto-generated method stub
        super.onStop();
        isRunning=false;
    }
}

kayout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:id="@+id/tx1"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:background="#FFFFFFFF" 
    android:text=""
    />
    <TextView  
    android:id="@+id/tx2"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:background="#FFFFFFFF" 
    android:text=""
    />
    <TextView  
    android:id="@+id/tx3"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:background="#FFFFFFFF" 
    android:text=""
    />
    <TextView  
    android:id="@+id/tx4"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:background="#FFFFFFFF" 
    android:text=""
    />
    <EditText
    android:id="@+id/bbb"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:text="not ready "
    />
</LinearLayout>

Good luck,

Answer 3

You can achieve this by creating Animation sequences, in either XML or Java code, and triggering them in sequence. You will need to define a animation sequence with LayoutAnimationController, at the end of the animation, you can add the ClickListener.

Developer Life has a good tutorial to get you started on animations. Jeff has a two-part tutorial series on animations - part 1, part 2.

Hope this helps, indyfromoz