Thursday, 22 September 2011

Displaying a Progress Dialog

Besides the plain dialog that you created in the previous section, you can also create a progress dialog.
A progress dialog is useful for showing the progress of some activities, such as the status of a download
operation.
The following Try It Out shows you how to display a progress dialog.
Displaying a Progress Dialog W Try It Out indow Using an Activity
1. Using the same project created in the previous section, add the following statements in bold to the
MainActivity.java file:
package net.learn2develop.Dialog;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import android.app.ProgressDialog;
import android.os.Handler;
import android.os.Message;
public class MainActivity extends Activity {
CharSequence[] items = { “Google”, “Apple”, “Microsoft” };
boolean[] itemsChecked = new boolean [items.length];
private ProgressDialog _progressDialog;
private int _progress = 0;
private Handler _progressHandler;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btn = (Button) findViewById(R.id.btn_dialog);
btn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
showDialog(1);
_progress = 0;
_progressDialog.setProgress(0);
_progressHandler.sendEmptyMessage(0);
}
});
_progressHandler = new Handler() {
public void handleMessage(Message msg) {
super.handleMessage(msg);
if (_progress >= 100) {
_progressDialog.dismiss();
} else {
_progress++;
_progressDialog.incrementProgressBy(1);
_progressHandler.sendEmptyMessageDelayed(0, 100);
}
}
};
}
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case 0:
return new AlertDialog.Builder(this)
//...
//...
.create();
case 1:
_progressDialog = new ProgressDialog(this);
_progressDialog.setIcon(R.drawable.icon);
_progressDialog.setTitle(“Downloading files...”);
_progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
_progressDialog.setButton(DialogInterface.BUTTON_POSITIVE, “Hide”, new
DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int whichButton)
{
Toast.makeText(getBaseContext(),
“Hide clicked!”, Toast.LENGTH_SHORT).show();
}
});
_progressDialog.setButton(DialogInterface.BUTTON_NEGATIVE, “Cancel”, new
DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int whichButton)
{
Toast.makeText(getBaseContext(),
“Cancel clicked!”, Toast.LENGTH_SHORT).show();
}
});
return _progressDialog;
}
return null;
}
}
2. Press F11 to debug the application on the Android Emulator. Click the button to display the progress
dialog (see Figure 2-8). Observe that the progress bar will count up to 100.

                     Fig- Showing displayed progressed bar

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