Pinch zoom on imageview example in Android

Here the below example is shown how to apply pinch zoom controls on imageview in android.

To apply pinch zoom controls first off all create custom view class which extends imageview.

Apply touch controls in custom view class.


ZoomImageView.java(This is the custom view class)

package com.androidsurya.imagepinchzoom;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;

public class ZoomImageView extends ImageView {
Matrix matrix = new Matrix();

static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
static final int CLICK = 3;
int mode = NONE;

PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 4f;
float[] m;

float redundantXSpace, redundantYSpace;
float width, height;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;

ScaleGestureDetector mScaleDetector;
Context context;

public ZoomImageView(Context context, AttributeSet attr) {
super(context, attr);
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);

setOnTouchListener(new OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);

matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());

switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = ZOOM;
break;
case MotionEvent.ACTION_MOVE:
if (mode == ZOOM || (mode == DRAG && saveScale > minScale)) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
} else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
} else {
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);

if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;

case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;

case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true;
}

});
}

@Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}

public void setMaxZoom(float x) {
maxScale = x;
}

private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {

@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}

@Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width
- (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width
|| origHeight * saveScale <= height) {
matrix.postScale(mScaleFactor, mScaleFactor, width / 2,
height / 2);
if (mScaleFactor < 1) {
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (Math.round(origWidth * saveScale) < width) {
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
} else {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
} else {
matrix.postScale(mScaleFactor, mScaleFactor,
detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
// Fit to screen.
float scale;
float scaleX = width / bmWidth;
float scaleY = height / bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;

// Center the image
redundantYSpace = height - (scale * bmHeight);
redundantXSpace = width - (scale * bmWidth);
redundantYSpace /= 2;
redundantXSpace /= 2;

matrix.postTranslate(redundantXSpace, redundantYSpace);

origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
}

Use this custom class instead of imageview in layout of your project with fully qualified name.

main.xml(UI Layout)

<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" >

    <com.androidsurya.imagepinchzoom.ZoomImageView
        android:id="@+id/zoomimg"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>


MainActivity.java (Activity to created object to view and assign bitmap to custom view)

package com.androidsurya.imagepinchzoom;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.os.Bundle;

public class MainActivity extends Activity {
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
PointF startPoint = new PointF();
PointF midPoint = new PointF();
float oldDist = 1f;
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
ZoomImageView ZoomImageView;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ZoomImageView = (ZoomImageView) findViewById(R.id.zoomimg);
Bitmap bitmapImage = BitmapFactory.decodeResource(
getApplicationContext().getResources(), R.drawable.image);
ZoomImageView.setImageBitmap(bitmapImage);

}
}

Android Manifest file(Register activity in Manifest file)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.androidsurya.imagepinchzoom"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="8" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.androidsurya.imagepinchzoom.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>

Output Screenshot:

How To Apply Rounded Corners to Layout in Android

Here below example shows how to set Rounded corners to Layout

Create (round.xml) file in drawable folder of your project
Copy below code:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
   android:padding="10dp"
   android:shape="rectangle" >
    <solid android:color="#FFFFFFFF" />
    <corners android:radius="20dp" />
</shape>

Use this layout as background to Layout
<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"
    tools:context=".RoundedCornerEditText"
    android:background="@android:color/darker_gray">
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:layout_centerVertical="true"
        android:layout_marginRight="76dp"
        android:background="@drawable/round" >
        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Button" />
        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="86dp"
            android:layout_marginTop="156dp"
            android:src="@drawable/ic_launcher" />
    </LinearLayout>

</RelativeLayout>

Output Screenshot:

Note: 

Like this u can apply this(round.xml)layout as background to any view.

Rounded corner Edittext in android

Here below example shows how to set Rounded corners to EditText

Create (round.xml) file in drawable folder of your project 

Copy below code:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:padding="10dp"
    android:shape="rectangle" >
    <solid android:color="#FFFFFFFF" />
    <corners android:radius="20dp" />
</shape>

Use this layout as background to EditText

<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:background="@android:color/darker_gray"
    tools:context=".RoundedCornerEditText" >

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:background="@drawable/round"
        android:ems="10"
        android:padding="5dp"
        android:text="Hi am rounded corner EditText Box"
        android:textSize="15dp" />

</RelativeLayout>

Output ScreenShot:

How to use default Android drawables ?

So many people don't know use default android drawables in android project
Here we can see how to use defalut drawables

We can assign (use) defalut drawables 2 ways
 
1)Assign in Programatically (In Activity)
Example:

Button search = (Button) findViewById(R.id.search);
seach.setBackgroundColor(android.R.drawable.ic_search_category_default);

2)Assign in XML (Layout-Resource Usage)
Example:

<Button
        android:id="@+id/search"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@android:drawable/ic_search_category_default" />

List of the drawables in Android 1.5:
http://www.darshancomputing.com/android/1.5-drawables.html