将缩放添加到Android中的imageview

我想在我的Android应用中添加缩放function。 我试过这段代码，但它只是在图像中间放大和缩小，我想在整个图像上应用缩放。

在同一图像中，我可以在图像的某些区域放置一个按钮吗？

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; } } 

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)); } } 

我该如何解决这个问题？

Answer 1

请尝试以下代码。 我认为它会成功。

 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; } }