Sunday, 27 January 2013

AsyncTask in Android(2)

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:padding="@dimen/padding_medium"
        android:text="@string/async_task"
        tools:context=".AsyncTaskActivity" />

    <ProgressBar
        android:id="@+id/progress"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="34dp" />

    <Button
        android:id="@+id/btn_start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/progress"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="40dp"
        android:minWidth="120dp"
        android:text="@string/start_btn" />

    <TextView
        android:id="@+id/txt_percentage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/progress"
        android:text="downloading  0%"
        android:textAppearance="?android:attr/textAppearanceMedium" />

</RelativeLayout>

MainActivity.java:
package com.async.ram;

import android.os.AsyncTask;
import android.os.Bundle;
import android.os.SystemClock;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

public class AsyncTaskActivity extends Activity {

Button btn_start;
ProgressBar progressBar;
TextView txt_percentage;

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

btn_start = (Button) findViewById(R.id.btn_start);
progressBar = (ProgressBar) findViewById(R.id.progress);
txt_percentage = (TextView) findViewById(R.id.txt_percentage);

btn_start.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {

btn_start.setEnabled(false);
new ShowDialogAsyncTask().execute();
}
});
}

private class ShowDialogAsyncTask extends AsyncTask<Void, Integer, Void> {

int progress_status;

@Override
protected void onPreExecute() {
// update the UI immediately after the task is executed
super.onPreExecute();

progress_status = 0;
txt_percentage.setText("downloading 0%");

}

@Override
protected Void doInBackground(Void... params) {

while (progress_status < 100) {

progress_status += 2;

publishProgress(progress_status);
SystemClock.sleep(300);

}
return null;
}

@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);

progressBar.setProgress(values[0]);
txt_percentage.setText("downloading " + values[0] + "%");

}

@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);

txt_percentage.setText("download complete");
btn_start.setEnabled(true);
}

}
}