Implement Pinch Zoom in OnTouchListener

Modify the last exercise of "Implement OnTouchListener to handle multi-touch event" to implement our own pinch detection.

package com.exercise.AndroidTouchPinchZoom;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.FloatMath;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
import android.widget.TextView;

public class AndroidTouchPinchZoomActivity extends Activity {
 
 TextView myTouchEvent;
 ImageView myImageView;
 Bitmap bitmap;
 int bmpWidth, bmpHeight;
 
 //Touch event related variables
 int touchState;
 final int IDLE = 0;
 final int TOUCH = 1;
 final int PINCH = 2;
 float dist0, distCurrent;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        myTouchEvent = (TextView)findViewById(R.id.touchevent);
        myImageView = (ImageView)findViewById(R.id.imageview);
        
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
        bmpWidth = bitmap.getWidth();
        bmpHeight = bitmap.getHeight();
        
        distCurrent = 1; //Dummy default distance
        dist0 = 1;   //Dummy default distance
        drawMatrix();
        
        myImageView.setOnTouchListener(MyOnTouchListener);
        touchState = IDLE;
    }
    
    private void drawMatrix(){
     float curScale = distCurrent/dist0;
     if (curScale < 0.1){
      curScale = 0.1f; 
     }
     
     Bitmap resizedBitmap;    
     int newHeight = (int) (bmpHeight * curScale);
     int newWidth = (int) (bmpWidth * curScale);
     resizedBitmap = Bitmap.createScaledBitmap(bitmap, newWidth, newHeight, false);
     myImageView.setImageBitmap(resizedBitmap); 
    }
    
    OnTouchListener MyOnTouchListener
    = new OnTouchListener(){

  @Override
  public boolean onTouch(View view, MotionEvent event) {
   // TODO Auto-generated method stub
   
   float distx, disty;
   
   switch(event.getAction() & MotionEvent.ACTION_MASK){
   case MotionEvent.ACTION_DOWN:
    //A pressed gesture has started, the motion contains the initial starting location.
    myTouchEvent.setText("ACTION_DOWN"); 
    touchState = TOUCH;
    break;
   case MotionEvent.ACTION_POINTER_DOWN:
    //A non-primary pointer has gone down.
    myTouchEvent.setText("ACTION_POINTER_DOWN"); 
    touchState = PINCH;
    
    //Get the distance when the second pointer touch
    distx = event.getX(0) - event.getX(1);
    disty = event.getY(0) - event.getY(1);
    dist0 = FloatMath.sqrt(distx * distx + disty * disty);

    break;
   case MotionEvent.ACTION_MOVE:
    //A change has happened during a press gesture (between ACTION_DOWN and ACTION_UP).
    myTouchEvent.setText("ACTION_MOVE");
    
    if(touchState == PINCH){      
     //Get the current distance
     distx = event.getX(0) - event.getX(1);
     disty = event.getY(0) - event.getY(1);
     distCurrent = FloatMath.sqrt(distx * distx + disty * disty);

     drawMatrix();
    }
    
    break;
   case MotionEvent.ACTION_UP:
    //A pressed gesture has finished.
    myTouchEvent.setText("ACTION_UP"); 
    touchState = IDLE;
    break;
   case MotionEvent.ACTION_POINTER_UP:
    //A non-primary pointer has gone up.
    myTouchEvent.setText("ACTION_POINTER_UP"); 
    touchState = TOUCH;
    break;
   }
   
   return true;
  }
     
    };
}

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

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />
    <TextView
        android:id="@+id/touchevent"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />
    <ImageView
        android:id="@+id/imageview" 
        android:layout_gravity="center"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" 
        android:scaleType="center" />

</LinearLayout>

Download the files.


Related article:
- Scale bitmap according to ScaleGestureDetector

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Connect to SQL Azure Using ADO.NET

Sample code using ADO.NET to connect to a database in Microsoft SQL Azure Database is very similar to connecting to an instance of SQL Server on your premises

Using this Example

To use this example in Visual Studio with your SQL Azure server, do the following steps:

1. Open Visual Studio and create a new console application.
2. Replace the code in the program file with the code from this example.
3. Replace <ProvideUserName> with the name of an SQL Azure Database login that has been assigned the dbmanager role. Note: if you use the login@server username format, the server portion of the name must match the first part of the server's fully qualified name. For example, if your server is servername.database.windows.net, your login name will look like loginname@servername. For more information about SQL Azure Database roles.
4. Replace <ProvidePassword> with the password associated with the login. Note: We recommend using a strong password when creating a login.
5. Replace <ProvideServerName> with the fully qualified domain name of your SQL Azure server. For example: servername.database.windows.net
6. Replace <ProvideDatabaseName> with the name of the database you want the code to create.
7. Run the code.

' Sample Code

Option Explicit On

Option Strict On

Imports System

Imports System.Collections.Generic

Imports System.Linq

Imports System.Text

Imports System.Data.SqlClient

Imports System.Data

Module Program

    ' Provide the following information

    Private ReadOnly userName As String = "<ProvideUserName>"

    Private ReadOnly password As String = "<ProvidePassword>"

    Private ReadOnly dataSource As String = "<ProvideServerName>"

    Private ReadOnly sampleDatabaseName As String = "<ProvideDatabaseName>"

    Sub Main()

        ' Create a connection string for the master database

        Dim connString1Builder As New SqlConnectionStringBuilder()

        With connString1Builder

            .DataSource = dataSource

            .InitialCatalog = "master"

            .Encrypt = True

            .TrustServerCertificate = False

            .UserID = userName

            .Password = password

        End With

        ' Create a connection string for the sample database

        Dim connString2Builder As New SqlConnectionStringBuilder()

        With connString2Builder

            .DataSource = dataSource

            .InitialCatalog = sampleDatabaseName

            .Encrypt = True

            .TrustServerCertificate = False

            .UserID = userName

            .Password = password

        End With

        ' Connect to the master database and create the sample database

        Using conn As New SqlConnection(connString1Builder.ToString())

            Using command As SqlCommand = conn.CreateCommand()

                conn.Open()

                ' Create the sample database

                Dim cmdText As String

                cmdText = String.Format("CREATE DATABASE {0}", _

                                        sampleDatabaseName)

                command.CommandText = cmdText

                command.ExecuteNonQuery()

                conn.Close()

            End Using

        End Using

        ' Connect to the sample database and perform various operations

        Using conn As New SqlConnection(connString2Builder.ToString())

            Using command As SqlCommand = conn.CreateCommand()

                conn.Open()

                ' Create a table

                command.CommandText = "CREATE TABLE T1(Col1 int primary key, Col2 varchar(20))"

                command.ExecuteNonQuery()

                ' Insert sample records

                command.CommandText = "INSERT INTO T1 (col1, col2) VALUES (1, 'string 1'), (2, 'string 2'), (3, 'string 3')"

                Dim rowsAdded As Integer = command.ExecuteNonQuery()

                ' Query the table and print the results

                command.CommandText = "SELECT * FROM T1"

                Using reader As SqlDataReader = command.ExecuteReader()

                    ' Loop over the results

                    While reader.Read()

                        Console.WriteLine("Col1: {0}, Col2: {1}", _

                                          reader("Col1").ToString().Trim(), _

                                          reader("Col2").ToString().Trim())

                    End While

                End Using

                ' Update a record

                command.CommandText = "UPDATE T1 SET Col2='string 1111' WHERE Col1=1"

                command.ExecuteNonQuery()

                ' Delete a record

                command.CommandText = "DELETE FROM T1 WHERE Col1=2"

                command.ExecuteNonQuery()

                ' Query the table and print the results

                Console.WriteLine("After update/delete, the table has these records...")

                command.CommandText = "SELECT * FROM T1"

                Using reader As SqlDataReader = command.ExecuteReader()

                    ' Loop over the results

                    While reader.Read()

                        Console.WriteLine("Col1: {0}, Col2: {1}", _

                                          reader("Col1").ToString().Trim(), _

                                          reader("Col2").ToString().Trim())

                    End While

                End Using

                conn.Close()

            End Using

        End Using

        Console.WriteLine("Press Enter to continue...")

        Console.ReadLine()

    End Sub

End Module

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