[英]Add zoom to an imageview in Android
I want to add zoom in my Android app. 我想在我的Android应用程序中添加缩放。 I have tried this code, but it just zooms in and out in the middle of the image and I want to apply the zoom on the whole image. 我已经尝试过此代码,但是它只是在图像的中间进行放大和缩小,因此我想将缩放应用于整个图像。
In the same image, can I put a button in some areas in the image? 在同一张图片中,我可以在图片的某些区域放置按钮吗?
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.view.KeyEvent;
import android.view.View;
public class Zoom extends View {
private Drawable image;
private int zoomControler=20;
public Zoom(Context context)
{
super(context);
image=context.getResources().getDrawable(R.drawable.icon);
setFocusable(true);
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
//Here you can control the width and height of the images........ this line is very important
image.setBounds((getWidth()/2)-zoomControler, (getHeight()/2)-zoomControler, (getWidth()/2)+zoomControler, (getHeight()/2)+zoomControler);
image.draw(canvas);
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode==KeyEvent.KEYCODE_DPAD_UP)// zoom in
zoomControler+=10;
if(keyCode==KeyEvent.KEYCODE_DPAD_DOWN) // zoom out
zoomControler-=10;
if(zoomControler<10)
zoomControler=10;
invalidate();
return true;
}
}
And this code 而这段代码
import android.app.Activity;
import android.os.Bundle;
public class zooming extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(new Zoom(this));
}
}
How do I fix this problem? 我该如何解决这个问题?
Try the following code. 请尝试以下代码。 I think it will work out. 我认为它将解决。
import android.app.Activity;
import android.os.Bundle;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.view.Display;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
public class ZoomHelloActivity extends Activity {
// Physical display width and height.
private static int displayWidth = 0;
private static int displayHeight = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Display display = ((WindowManager)
getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
displayWidth = display.getWidth();
displayHeight = display.getHeight();
setContentView(new SampleView(this));
}
private static class SampleView extends View {
private static Bitmap bmLargeImage; //bitmap large enough to be scrolled
private static Rect displayRect = null; //rect we display to
private Rect scrollRect = null; //rect we scroll over our bitmap with
private int scrollRectX = 0; //current left location of scroll rect
private int scrollRectY = 0; //current top location of scroll rect
private float scrollByX = 0; //x amount to scroll by
private float scrollByY = 0; //y amount to scroll by
private float startX = 0; //track x from one ACTION_MOVE to the next
private float startY = 0; //track y from one ACTION_MOVE to the next
public SampleView(Context context) {
super(context);
// Destination rect for our main canvas draw. It never changes.
displayRect = new Rect(0, 0, displayWidth, displayHeight);
// Scroll rect: this will be used to 'scroll around' over the
// bitmap in memory. Initialize as above.
scrollRect = new Rect(0, 0, displayWidth, displayHeight);
// Load a large bitmap into an offscreen area of memory.
bmLargeImage = BitmapFactory.decodeResource(getResources(),
R.drawable.icon);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// Remember our initial down event location.
startX = event.getRawX();
startY = event.getRawY();
break;
case MotionEvent.ACTION_MOVE:
float x = event.getRawX();
float y = event.getRawY();
// Calculate move update. This will happen many times
// during the course of a single movement gesture.
scrollByX = x - startX; //move update x increment
scrollByY = y - startY; //move update y increment
startX = x; //reset initial values to latest
startY = y;
invalidate(); //force a redraw
break;
}
return true; //done with this event so consume it
}
@Override
protected void onDraw(Canvas canvas) {
int newScrollRectX = scrollRectX - (int)scrollByX;
int newScrollRectY = scrollRectY - (int)scrollByY;
// Don't scroll off the left or right edges of the bitmap.
if (newScrollRectX < 0)
newScrollRectX = 0;
else if (newScrollRectX > (bmLargeImage.getWidth() - displayWidth))
newScrollRectX = (bmLargeImage.getWidth() - displayWidth);
// Don't scroll off the top or bottom edges of the bitmap.
if (newScrollRectY < 0)
newScrollRectY = 0;
else if (newScrollRectY > (bmLargeImage.getHeight() - displayHeight))
newScrollRectY = (bmLargeImage.getHeight() - displayHeight);
// We have our updated scroll rect coordinates, set them and draw.
scrollRect.set(newScrollRectX, newScrollRectY,
newScrollRectX + displayWidth, newScrollRectY + displayHeight);
Paint paint = new Paint();
canvas.drawBitmap(bmLargeImage, scrollRect, displayRect, paint);
// Reset current scroll coordinates to reflect the latest updates,
// so we can repeat this update process.
scrollRectX = newScrollRectX;
scrollRectY = newScrollRectY;
}
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.