ARUNKUMAR

Friday, October 26, 2012

Custom Expandable List Example

Description:
This example shows how to create Expandable list using custom adapter.
Algorithm:

1.) Create a new project by File-> New -> Android Project name it CustomExpandableListExample.
2.) Run for output.

Steps:
1.) Create a project named CustomExpandableListExample and set the information as stated in the image.

Build Target: Android 2.3.3
Application Name: CustomExpandableListExample
Package Name: com.example
Activity Name: CustomExpandableListExampleActivity
Min SDK Version: 10

2.) Open CustomExpandableListExampleActivity.java file and write following code there:

package com.example;

import android.app.ExpandableListActivity;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.ContextMenu.ContextMenuInfo;

import android.view.Gravity;

import android.view.MenuItem;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AbsListView;

import android.widget.BaseExpandableListAdapter;

import android.widget.ExpandableListAdapter;

import android.widget.ExpandableListView;

import android.widget.ExpandableListView.ExpandableListContextMenuInfo;

import android.widget.TextView;

import android.widget.Toast;

public class CustomExpandableListExampleActivity extends ExpandableListActivity {

    ExpandableListAdapter mAdapter;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        // Set up our adapter

        mAdapter = new MyExpandableListAdapter();

        setListAdapter(mAdapter);

        registerForContextMenu(getExpandableListView());

    }

    @Override

    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {

        menu.setHeaderTitle("Sample menu");

        menu.add(0, 0, 0, "Sample action");

    }

    @Override

    public boolean onContextItemSelected(MenuItem item) {

        ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item.getMenuInfo();

        String title = ((TextView) info.targetView).getText().toString();

        int type = ExpandableListView.getPackedPositionType(info.packedPosition);

        if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {

            int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); 

            int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition); 

            Toast.makeText(this, title + ": Child " + childPos + " clicked in group " + groupPos,

                    Toast.LENGTH_SHORT).show();

            return true;

        } else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) {

            int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); 

            Toast.makeText(this, title + ": Group " + groupPos + " clicked", Toast.LENGTH_SHORT).show();

            return true;

        }

        return false;

    }

    public class MyExpandableListAdapter extends BaseExpandableListAdapter {

        // Sample data set.  children[i] contains the children (String[]) for groups[i].

        private String[] groups = { "Names", "Designation", "Gender", "Company" };

        private String[][] children = {

                { "abc", "xyz", "ash", "anu" },

                { "SSE", "TJ", "PM", "SE" },

                { "Male", "Female" },

                { "yyyyyy", "xxxxx" }

        };

        public Object getChild(int groupPosition, int childPosition) {

            return children[groupPosition][childPosition];

        }

        public long getChildId(int groupPosition, int childPosition) {

            return childPosition;

        }

        public int getChildrenCount(int groupPosition) {

            return children[groupPosition].length;

        }

        public TextView getGenericView() {

            // Layout parameters for the ExpandableListView

            AbsListView.LayoutParams lp = new AbsListView.LayoutParams(

                    ViewGroup.LayoutParams.MATCH_PARENT, 64);

            TextView textView = new TextView(CustomExpandableListExampleActivity.this);

            textView.setLayoutParams(lp);

            // Center the text vertically

            textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);

            // Set the text starting position

            textView.setPadding(36, 0, 0, 0);

            return textView;

        }

        public View getChildView(int groupPosition, int childPosition, boolean isLastChild,

                View convertView, ViewGroup parent) {

            TextView textView = getGenericView();

            textView.setText(getChild(groupPosition, childPosition).toString());

            return textView;

        }

        public Object getGroup(int groupPosition) {

            return groups[groupPosition];

        }

        public int getGroupCount() {

            return groups.length;

        }

        public long getGroupId(int groupPosition) {

            return groupPosition;

        }

        public View getGroupView(int groupPosition, boolean isExpanded, View convertView,

                ViewGroup parent) {

            TextView textView = getGenericView();

            textView.setText(getGroup(groupPosition).toString());

            return textView;

        }

        public boolean isChildSelectable(int groupPosition, int childPosition) {

            return true;

        }

        public boolean hasStableIds() {

            return true;

        }

    }

}

3.) Compile and build the project.

Output

Friday, August 24, 2012

Conversion to Dalvik format failed with error 1" Error in ANDROID / Eclipse.

This is a normal error when you import some project into eclipse.
I will show you how to solve this

First try cleaning the project from project->Clean.
If this didn’t work, then try these

Follow these steps
1. Go to Project » Properties » Java Build Path » Libraries and remove all except the “Android X.Y” (eg: Android 1.5). click OK.
2. Go to Project » Clean » Clean projects selected below » select your project and click OK.

Now your error may be gone.
Happy coding…

Friday, August 17, 2012

ImageSwitcher View in android

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ff000000"
>

<ImageSwitcher
android:id="@+id/switcher1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"
/>
<Gallery
android:id="@+id/gallery1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>

</RelativeLayout>
Modify the DisplayViewsExample.java file as shown below:
package net.learn2develop.AndroidViews;

import android.app.Activity;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.Gallery.LayoutParams;
import android.widget.ViewSwitcher.ViewFactory;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;

public class DisplayViewsExample extends Activity
implements ViewFactory
{
//---the images to display---
Integer[] imageIDs = {
R.drawable.pic1,
R.drawable.pic2,
R.drawable.pic3,
R.drawable.pic4,
R.drawable.pic5,
R.drawable.pic6,
R.drawable.pic7
};

private ImageSwitcher imageSwitcher;

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

imageSwitcher = (ImageSwitcher) findViewById(R.id.switcher1);
imageSwitcher.setFactory(this);
imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));
imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));

Gallery gallery = (Gallery) findViewById(R.id.gallery1);
gallery.setAdapter(new ImageAdapter(this));
gallery.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView parent,
View v, int position, long id)
{
imageSwitcher.setImageResource(imageIDs[position]);
}
});
}

public View makeView()
{
ImageView imageView = new ImageView(this);
imageView.setBackgroundColor(0xFF000000);
imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
imageView.setLayoutParams(new
ImageSwitcher.LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
return imageView;
}

public class ImageAdapter extends BaseAdapter
{
private Context context;
private int itemBackground;

public ImageAdapter(Context c)
{
context = c;

//---setting the style---
TypedArray a = obtainStyledAttributes(R.styleable.Gallery1);
itemBackground = a.getResourceId(
R.styleable.Gallery1_android_galleryItemBackground, 0);
a.recycle();
}

//---returns the number of images---
public int getCount()
{
return imageIDs.length;
}

//---returns the ID of an item---
public Object getItem(int position)
{
return position;
}

public long getItemId(int position)
{
return position;
}

//---returns an ImageView view---
public View getView(int position, View convertView, ViewGroup parent)
{
ImageView imageView = new ImageView(context);
imageView.setImageResource(imageIDs[position]);
imageView.setScaleType(ImageView.ScaleType.FIT_XY);
imageView.setLayoutParams(new Gallery.LayoutParams(150, 120));
imageView.setBackgroundResource(itemBackground);
return imageView;
}
}
}
Observe that the DisplayViewsExample class now implements the ViewFactory class. The ViewFactory class creates the views in a ViewSwitcher view. When your class implements the ViewFactory class, you need to override the makeView() method, which creates a new View to be added in a ViewSwitcher.
Press F11 in Eclipse and observe the ImageSwitcher in action as shown in Figure 13.

Android DisplayMetrics

Get screen resolution using android.util.DisplayMetrics
android.util.DisplayMetrics is a structure describing general information about a display, such as its size, density, and font scaling.

To use android.util.DisplayMetrics to get resolution:

Create a dummy Android Application, add a TextView in main.xml to display the result.

<TextView
android:id="@+id/strScreenSize"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=""
/>

Modify the .java file to read DisplayMetrics

package com.exercise.AndroidScreen;

import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.widget.TextView;

public class AndroidScreenActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
String str_ScreenSize = "The Android Screen is: "
+ dm.widthPixels
+ " x "
+ dm.heightPixels;

TextView mScreenSize = (TextView) findViewById(R.id.strScreenSize);
mScreenSize.setText(str_ScreenSize);
}
}

Thursday, August 16, 2012

Install Android APK Programmatically

To install app programmatically use following code, you'll need user permissions though.

Intent promptInstall = new Intent(Intent.ACTION_VIEW)
.setData(Uri.parse("file:///path/to/your.apk"))
.setType("application/vnd.android.package-archive";
startActivity(promptInstall);