Programming Java Introduction| Lecture 1| lập trình java basic|saka deverloper

Using android Camera surfaceView android studio

1. Create a New Android Application Project

2. Creating the layout of the main 

We are going to make a very simple layout xml for the CameraDemo

<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent">

    <RelativeLayout

        android:id="@+id/btn_layout"

        android:layout_width="match_parent"

        android:layout_height="match_parent">

        <RelativeLayout

            android:id="@+id/layout_area"

            android:layout_width="match_parent"

            android:layout_height="50dp"

            android:layout_alignParentTop="true"

            android:background="#000">

            <ImageView

                android:id="@+id/btn_flash"

                android:layout_width="50dp"

                android:layout_height="50dp"

                android:layout_alignParentLeft="true"

                android:padding="5dp"

                android:src="@drawable/ic_action_flash_off" />

            <ImageView

                android:id="@+id/btn_switch"

                android:layout_width="50dp"

                android:layout_height="50dp"

                android:layout_alignParentRight="true"

                android:padding="5dp"

                android:src="@drawable/ic_action_switch_camera" />

        </RelativeLayout>

        <SurfaceView

            android:id="@+id/surfaceView"

            android:layout_width="match_parent"

            android:layout_height="match_parent"

            android:layout_above="@+id/layout_area1"

            android:layout_below="@+id/layout_area" />

        <RelativeLayout

            android:id="@+id/layout_area1"

            android:layout_width="match_parent"

            android:layout_height="100dp"

            android:layout_alignParentBottom="true"

            android:background="#000">

            <ImageView

                android:id="@+id/btn_exit"

                android:layout_width="50dp"

                android:layout_height="50dp"

                android:layout_alignParentLeft="true"

                android:layout_centerVertical="true"

                android:src="@drawable/ic_action_remove" />

            <com.melnykov.fab.FloatingActionButton

                android:id="@+id/btn_take_photo"

                android:layout_width="60dp"

                android:layout_height="60dp"

                android:layout_centerInParent="true"

                android:src="@drawable/ic_action_camera" />

            <ImageView

                android:id="@+id/btn_lib"

                android:layout_width="50dp"

                android:layout_height="50dp"

                android:layout_alignParentRight="true"

                android:layout_centerVertical="true"

                android:layout_margin="5dp"

                android:src="@drawable/ic_library_cam" />

        </RelativeLayout>

    </RelativeLayout>

</FrameLayout>

3. Creating the source code

package com.example.tb_laota.camerademo;

import android.content.Intent;

import android.hardware.Camera;

import android.hardware.Camera.PictureCallback;

import android.hardware.Camera.ShutterCallback;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.support.v7.app.AppCompatActivity;

import android.view.SurfaceHolder;

import android.view.SurfaceView;

import android.view.View;

import android.widget.Toast;

import com.melnykov.fab.FloatingActionButton;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.text.SimpleDateFormat;

import java.util.Date;

import butterknife.ButterKnife;

import butterknife.InjectView;

/**

 * Created by tb_laota on 10/30/2015.

 */

public class CameraActivity extends AppCompatActivity implements SurfaceHolder.Callback {

    Camera camera;

    @InjectView(R.id.surfaceView)

    SurfaceView surfaceView;

    @InjectView(R.id.btn_take_photo)

    FloatingActionButton btn_take_photo;

    SurfaceHolder surfaceHolder;

    PictureCallback jpegCallback;

    ShutterCallback shutterCallback;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.camera_activity);

        ButterKnife.inject(this);

        surfaceHolder = surfaceView.getHolder();

        // Install a surfaceHolder.Callback so we get notified when the

        // underlying surface is created and destroyed.

        surfaceHolder.addCallback(this);

        //deprecated setting, but required on android versions prior to 3.0

        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        btn_take_photo.setOnClickListener(new FloatingActionButton.OnClickListener() {

            @Override

            public void onClick(View v) {

                captureImage();

            }

        });

        jpegCallback = new PictureCallback() {

            @Override

            public void onPictureTaken(byte[] data, Camera camera) {

                FileOutputStream outputStream = null;

                File file_image = getDirc();

                if (!file_image.exists() && !file_image.mkdirs()) {

                    Toast.makeText(getApplication(), "Can't create directory to save image", Toast.LENGTH_SHORT).show();

                    return;

                }

                SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyymmddhhmmss");

                String date = simpleDateFormat.format(new Date());

                String photofile = "Cam_Demo" + date + ".jpg";

                String file_name = file_image.getPath() + File.separator + photofile;

                File picfile = new File(file_name);

                try {

                    outputStream = new FileOutputStream(picfile);

                    outputStream.write(data);

                    outputStream.close();

                } catch (FileNotFoundException e) {

                } catch (IOException ex) {

                } finally {

                }

                Toast.makeText(getApplicationContext(), "Picture saved", Toast.LENGTH_SHORT).show();

                refreshCamera();

                refreshGallery(picfile);

            }

        };

    }

    //refresh gallery

    public void refreshGallery(File file) {

        Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);

        intent.setData(Uri.fromFile(file));

        sendBroadcast(intent);

    }

    public void refreshCamera() {

        if (surfaceHolder.getSurface() == null) {

            //preview surface does not exist

            return;

        }

        //stop preview before making changes

        try {

            camera.stopPreview();

        } catch (Exception e) {

        }

        //set preview size and make any resize, rotate or

        //reformatting changes here

        //start preview with new settings

        try {

            camera.setPreviewDisplay(surfaceHolder);

            camera.startPreview();

        } catch (Exception e) {

        }

    }

    public File getDirc() {

        File dics = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);

        return new File(dics, "Camera_Demo");

    }

    public void captureImage() {

        //take the picture

        camera.takePicture(null, null, jpegCallback);

    }

    @Override

    public void surfaceCreated(SurfaceHolder holder) {

        //open the camera

        try {

            camera = Camera.open();

        } catch (RuntimeException ex) {

        }

        Camera.Parameters parameters;

        parameters = camera.getParameters();

        //modify parameter

        parameters.setPreviewFrameRate(20);

        parameters.setPreviewSize(352, 288);

        camera.setParameters(parameters);

        camera.setDisplayOrientation(90);

        try {

            //The surface thas been created, now tell the camera where to draw

            //the preview

            camera.setPreviewDisplay(surfaceHolder);

            camera.startPreview();

        } catch (Exception e) {

        }

    }

    @Override

    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

        refreshCamera();

    }

    @Override

    public void surfaceDestroyed(SurfaceHolder holder) {

//stop preview and release camera

        camera.stopPreview();

        camera.release();

        camera = null;

    }

}

In these lines, we find our SurfaceView from our main layout and we get a holder, an abstract interface to someone holding a display surface. This, allows us to control the surface size and format, edit the pixels in the surface, and monitor changes to the surface. We also install a SurfaceHolder.Callback so we get notified when the underlying surface is created and destroyed. We have also written the surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); deprecated setting, but required on Android versions prior to 3.0.

4. Android Manifest

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.example.tb_laota.camerademo">

    <uses-permission android:name="android.permission.CAMERA" />

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-feature android:name="android.hardware.camera" />

    <uses-feature android:name="android.hardware.camera.autofocus" />

    <application

        android:allowBackup="true"

        android:icon="@mipmap/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme">

        <activity

            android:name=".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>

        <activity android:name=".CameraActivity"></activity>

    </application>

</manifest>

5. Build, compile and run

Android - XML Parser Tutorial use of XMLPullParser parse xml on web api|android studio

XML stands for Extensible Mark-up Language.XML is a very popular format and commonly used for sharing data on the internet. This chapter explains how to parse the XML file and extract necessary information from it.

XML-Parsing

we will create XMLPullParser object , but in order to create that we will first create XmlPullParserFactory object and then call its newPullParser() method to create XMLPullParser

Example:

Here is an example demonstrating the use of XMLPullParser class. It creates a basic Weather application that allows you to parse XML from google weather api and show the result.

Following is the content of the modified main activity file MainActivity.java.

package androiddemo.example.duyhoang.xmlparsedemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {
    private EditText txt1, txt2, txt3, txt4, txt5;
    private String url1 = "http://api.openweathermap.org/data/2.5/weather?q=";
    private String url2 = "&mode=xml";
    private HandleXml obj;
    Button btnWeather;

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnWeather = (Button) findViewById(R.id.btn_weather);

        txt1 = (EditText) findViewById(R.id.txtLocation);
        txt2 = (EditText) findViewById(R.id.txt_curency);
        txt3 = (EditText) findViewById(R.id.txt_temp);
        txt4 = (EditText) findViewById(R.id.txt_humidity);
        txt5 = (EditText) findViewById(R.id.txt_pressure);
        btnWeather.setOnClickListener(new View.OnClickListener() {
            @Override            public void onClick(View view) {
                String url = txt1.getText().toString();
                String finalUrl = url1 + url + url2;
                txt2.setText(finalUrl);
                obj = new HandleXml(finalUrl);
                obj.fetchXML();

                while (obj.parsingComplete) ;
                txt2.setText(obj.getCountry());
                txt3.setText(obj.getTemperature());
                txt4.setText(obj.getHumidity());
                txt5.setText(obj.getPressure());

            }
        });
    }

    @Override    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.        int id = item.getItemId();

        //noinspection SimplifiableIfStatement        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Following is the content of src/com.example.xmlparser/HandleXML.java.

package androiddemo.example.duyhoang.xmlparsedemo;

import android.util.Xml;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserFactory;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/** * Created by DUYHOANG on 9/10/2015. */public class HandleXml {
    private String country = "country";
    private String temperature = "temperature";
    private String humidity = "humidity";
    private String pressure = "pressure";
    private String urlString = null;
    private XmlPullParserFactory xmlFactoryObject;
    public volatile boolean parsingComplete = true;

    public HandleXml(String url) {
        this.urlString = url;
    }

    public String getCountry() {
        return country;
    }

    public String getTemperature() {
        return temperature;
    }

    public String getHumidity() {
        return humidity;
    }

    public String getPressure() {
        return pressure;
    }

    public void parseXMLAndStorelt(XmlPullParser myParser) {
        int event;
        String text = null;
        try {
            event = myParser.getEventType();
            while (event != XmlPullParser.END_DOCUMENT) {
                String name = myParser.getName();
                switch (event) {
                    case XmlPullParser.START_TAG:
                        break;
                    case XmlPullParser.TEXT:
                        text = myParser.getText();
                        break;
                    case XmlPullParser.END_TAG:
                        if (name.equals("country")) {
                            country = text;
                        } else if (name.equals("humidity")) {
                            humidity = myParser.getAttributeValue(null, "value");
                        } else if (name.equals("pressure")) {
                            pressure = myParser.getAttributeValue(null, "value");
                        } else if (name.equals("temperature")) {
                            temperature = myParser.getAttributeValue(null, "value");
                        } else {
                        }
                        break;
                }
                event = myParser.next();
            }
            parsingComplete = false;
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void fetchXML() {
        Thread thread = new Thread(new Runnable() {
            @Override            public void run() {
                try {
                    URL url = new URL(urlString);
                    HttpURLConnection connect = (HttpURLConnection) url.openConnection();
                    connect.setReadTimeout(10000);
                    connect.setConnectTimeout(15000);
                    connect.setRequestMethod("GET");
                    connect.setDoInput(true);
                    connect.connect();

                    InputStream stream = connect.getInputStream();
                    xmlFactoryObject = XmlPullParserFactory.newInstance();
                    XmlPullParser myparser = xmlFactoryObject.newPullParser();
                    myparser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
                    myparser.setInput(stream, null);
                    parseXMLAndStorelt(myparser);
                    stream.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
        thread.start();
    }
}

Following is the modified content of the xml res/layout/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"    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">

    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentTop="true"        android:layout_centerHorizontal="true"        android:text="@string/fetch"        android:textSize="30dp" />

    <TextView        android:id="@+id/textView2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_below="@+id/textView1"        android:layout_centerHorizontal="true"        android:gravity="center"        android:text="@string/weather_report"        android:textColor="@color/text_color"        android:textSize="30dp"        android:textStyle="bold" />

    <EditText        android:id="@+id/txtLocation"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@+id/textView2"        android:hint="@string/Location" />

    <Button        android:id="@+id/btn_weather"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_below="@+id/txtLocation"        android:layout_centerHorizontal="true"        android:text="@string/weather" />

    <LinearLayout        android:id="@+id/linearLayout1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@id/btn_weather"        android:orientation="vertical">

        <EditText            android:id="@+id/txt_curency"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:text="@string/curency"            />

        <EditText            android:id="@+id/txt_temp"            android:text="@string/temp"            android:layout_width="match_parent"            android:layout_height="wrap_content" />

        <EditText            android:id="@+id/txt_humidity"            android:text="@string/humidity"            android:layout_width="match_parent"            android:layout_height="wrap_content" />

        <EditText            android:id="@+id/txt_pressure"            android:text="@string/pressure"            android:layout_width="match_parent"            android:layout_height="wrap_content" />
    </LinearLayout>

</RelativeLayout>

Following is the content of AndroidManifest.xml file.
<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="androiddemo.example.duyhoang.xmlparsedemo" >
    <uses-permission android:name="android.permission.INTERNET"/>
    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >
        <activity            android:name=".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>
Thank's for watching. good luck!!!

Displaying a dialog using an activity in android tutorial

Displaying a dialog using an activity in android tutorial.

There are times where you need to display a dialog window to get a confirmation from the user. In 

this case, you can override the onCreateDialog()protected method defined in the base Activity

class to display a dialog window. The following Try It Out shows you how.

Now, create a new android project.

Edit interface in 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="com.example.demoshowdialog.MainActivity" >

    <Button

        android:id="@+id/btnShow_Dialog"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="Show Dialog" />

</RelativeLayout>

Next, the proccess code in MainActivity.java file:

package com.example.demoshowdialog;

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.view.View.OnClickListener;

import android.widget.Button;

public class MainActivity extends Activity {

       private Button btnShow_Dialog;

       CharSequence[] items = { "Asus", "Acer", "Dell", "Vaio" };

       boolean[] bool = new boolean[items.length];

       @Override

       protected void onCreate(Bundle savedInstanceState) {

          super.onCreate(savedInstanceState);

          setContentView(R.layout.activity_main);

          btnShow_Dialog = (Button) findViewById(R.id.btnShow_Dialog);

          btnShow_Dialog.setOnClickListener(new OnClickListener() {

             @Override

             public void onClick(View v) {

                 showDialog(0);

             }

          });

       }

       @Override

       protected Dialog onCreateDialog(int id) {

          // TODO Auto-generated method stub

          switch (id) {

          case 0:

              return new AlertDialog.Builder(this)

              .setIcon(R.drawable.ic_launcher)

              .setTitle("Show Dialog Demo")

              .setPositiveButton("Yes",new DialogInterface.OnClickListener() {

                             @Override

                             public void onClick(DialogInterface dialog,int which) {

                             // TODO Auto-generated method stub

                             }

                   })

              .setNegativeButton("No",new DialogInterface.OnClickListener() {

                             @Override

                             public void onClick(DialogInterface dialog, int which) {

                             // TODO Auto-generated method stub

                             }

                   })

              .setMultiChoiceItems(items, bool,new DialogInterface.OnMultiChoiceClickListener() {

              @Override

              public void onClick(DialogInterface dialog,int which, boolean isChecked) {

                                                              // TODO Auto-generated method stub

                    }

              }).create();

              }

              return null;

       }

}

Explain:
To display a dialog, you first override the onCreateDialog() method in the Activity class

@Override

       protected Dialog onCreateDialog(int id) {

...

}
This method is called when you call the showDialog() method

btnShow_Dialog = (Button) findViewById(R.id.btnShow_Dialog);

              btnShow_Dialog.setOnClickListener(new OnClickListener() {

                     @Override

                     public void onClick(View v) {

                           showDialog(0);

                     }

              });

The onCreateDialog() method is a callback for creating dialogs that are managed by the activity. When you call the showDialog() method, this callback will be invoked. The showDialog() method accepts an integer argument identifying a particular dialog to display.

Download source code: updating...