Hi friends let us learn how to create a camera based application in android.
Now you will use the function startActivityForResult
No matter which function you used to launch the activity , they all
return the result. The result can be obtained by overriding the function
onActivityResult.
To experiment with this example , you need to run this on an actual device on which camera is supported.
Following is the content of the modified main activity file src/com.example.camera/MainActivity.java.
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Basics for capturing a image using existing camera in our mobile
You will use MediaStore.ACTION_IMAGE_CAPTURE to launch an existing camera application installed on your phone. Its syntax is given belowIntent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);Apart from the above , there are other availaible Intents provided by MediaStore. They are listed as follows
| Sr.No | Intent type and description |
|---|---|
| 1 | ACTION_IMAGE_CAPTURE_SECURE It returns the image captured from the camera , when the device is secured |
| 2 | ACTION_VIDEO_CAPTURE It calls the existing video application in android to capture video |
| 3 | EXTRA_SCREEN_ORIENTATION It is used to set the orientation of the screen to vertical or landscape |
| 4 | EXTRA_FULL_SCREEN It is used to control the user interface of the ViewImage |
| 5 | INTENT_ACTION_VIDEO_CAMERA This intent is used to launch the camea in the video mode |
| 6 | EXTRA_SIZE_LIMIT It is used to specify the size limit of video or image capture size |
startActivityForResult(intent,0)This method has been defined in the activity class. We are calling it from main activity. There are methods defined in the activity class that does the same job , but used when you are not calling from the activity but from somewhere else. They are listed below
| Sr.No | Activity function description |
|---|---|
| 1 | startActivityForResult It starts an activity , but can take extra bundle of options with it |
| 2 | startActivityFromChild It launch the activity when your activity is child of any other activity |
| 3 | startActivityFromChild It work same as above , but it can take extra values in the shape of bundle with it |
| 4 | startActivityFromFragment It launches activity from the fragment you are currently inside |
| 5 | startActivityFromFragment It not only launches the activity from the fragment , but can take extra values with it |
Example
Here is an example that shows how to launch the exisitng camera application to capture an image and display the result in the form of bitmapTo experiment with this example , you need to run this on an actual device on which camera is supported.
| Steps | Description |
|---|---|
| 1 | You will use Eclipse IDE to create an Android application and name it as Camera under a package com.example.camera. While creating this project, make sure you Target SDK and Compile With at the latest version of Android SDK to use higher levels of APIs. |
| 2 | Modify src/MainActivity.java file to add intent code to launch the activity and result method to recieve the output. |
| 3 | Modify layout XML file res/layout/activity_main.xml add any GUI component if required. Here we add only imageView and a textView. |
| 4 | Modify res/values/strings.xml to define required constant values |
| 5 | Run the application and choose a running android device and install the application on it and verify the results. |
package com.example.camera; import android.os.Bundle; import android.app.Activity; import android.content.Intent; import android.graphics.Bitmap; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.ImageView; public class MainActivity extends Activity { ImageView imgFavorite; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); imgFavorite = (ImageView)findViewById(R.id.imageView1); imgFavorite.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { open(); } }); } public void open(){ Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); startActivityForResult(intent, 0); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub super.onActivityResult(requestCode, resultCode, data); Bitmap bp = (Bitmap) data.getExtras().get("data"); imgFavorite.setImageBitmap(bp); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }Following will be the content of res/layout/activity_main.xml file:
<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" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity"> <ImageView android:id="@+id/imageView1" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_marginLeft="34dp" android:layout_marginTop="36dp" android:contentDescription="@string/hello_world" android:src="@drawable/ic_launcher" /> <TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_alignRight="@+id/imageView1" android:text="@string/tap" android:textAppearance="?android:attr/textAppearanceLarge" /> </RelativeLayout>Following will be the content of res/values/strings.xml to define one new constants
<?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">Camera</string> <string name="action_settings">Settings</string> <string name="hello_world">Hello world!</string> <string name="tap">Tap the image to open the camera!!</string> </resources>Following is the default content of AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.camera" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="com.example.camera.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>Let's try to run your Camera application. I assume you have connected your actual Android Mobile device with your computer. To run the app from Eclipse, open one of your project's activity files and click Run
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