问题
I am new to android. I am working on project in which I have an image view and 2 buttons and 10 images in drawable. With button cliks images are changing perfectly but I dont know how to zoom these images. I applied most of the methods of pinch zoom in it but remained unsuccessful. Plz help with code.Especially in main java.
Main java
Public class MainActivity extends Activity {
Private ImageView hImageViewPic;
Private Button iButton, gButton;
Private int currentImage=0;
Int images []={R.drawable.a1, R.drawable.a2,//and so on}
@Override
Protected void onCreat (bundle savedInstanceState){
Super.onCreat (SavedInstanceState);
SetContentView (R.layout.activity_main);
Intent i=getIntent ();
Int position=i.getExtras ().getInt ("id");
hImageViewPic=(ImageView) findViewById (R.id.idImageViewPic);
iButton=(Button) findViewById (R.id.bIleri);
gButton=(Button) findViewById (R.id.bGeri);
iButton.setOnClickListener (i ButtonChangeImageListener);
gButton.setOnClickListener (gButtonChangeImageListener);
}
View.onClickListener iButtonChangeImageListener=new onClickListener (){
Public void onClick (View v){
currentImage++;
currentImage=currentImage%images.length;
hImageViewPic.setImageResource (images [currentImage]);
}
};
View.onClickListener gButtonChangeImageListener=new OnClickListener (){
Public void onClick (View v){
currentImage--;
currentImage=(currntImage+images.length)% images.length;
hImageViewPic.setImageResource (images [currentImage]);
}
};
}
Main xml
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="fill"
android:orientation="vertical"
android:weightSum="100">
<ImageView
android:id="@+id/idImageViewPic"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="100"
android:adjustViewBounds="true"
android:background="#66FFFF"
android:maxHeight="91dip"
android:maxWidth="47dip"
android:padding="10dip"
android:src="@drawable/a0"/>
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<Button
android:id="@+id/bGeri"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="back">
</Button>
<Button
android:id="@+id/bIleri"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Next">
</Button>
</LinearLayout>
</LinearLayout>
回答1:
Use below custom class for ImageView.
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix matrix;
// We can be in one of these 3 states
static int NONE = 0;
static int DRAG = 1;
static int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 0.5f;
float maxScale = 3f;
float[] m;
int viewWidth, viewHeight;
static int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
public void resetView() {
// We can be in one of these 3 states
NONE = 0;
DRAG = 1;
ZOOM = 2;
mode = NONE;
// Remember some things for zooming
last = new PointF();
start = new PointF();
minScale = 0.5f;
maxScale = 3f;
CLICK = 3;
saveScale = 1f;
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
}
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(curr);
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float fixTransX = getFixDragTrans(deltaX, viewWidth, origWidth * saveScale);
float fixTransY = getFixDragTrans(deltaY, viewHeight, origHeight * saveScale);
matrix.postTranslate(fixTransX, fixTransY);
fixTrans();
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; // indicate event was handled
}
});
}
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;
}
if (origWidth * saveScale <= viewWidth || origHeight * saveScale <= viewHeight)
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2, viewHeight / 2);
else
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
fixTrans();
return true;
}
}
void fixTrans() {
matrix.getValues(m);
float transX = m[Matrix.MTRANS_X];
float transY = m[Matrix.MTRANS_Y];
float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
float fixTransY = getFixTrans(transY, viewHeight, origHeight * saveScale);
if (fixTransX != 0 || fixTransY != 0)
matrix.postTranslate(fixTransX, fixTransY);
}
float getFixTrans(float trans, float viewSize, float contentSize) {
float minTrans, maxTrans;
if (contentSize <= viewSize) {
minTrans = 0;
maxTrans = viewSize - contentSize;
} else {
minTrans = viewSize - contentSize;
maxTrans = 0;
}
if (trans < minTrans)
return -trans + minTrans;
if (trans > maxTrans)
return -trans + maxTrans;
return 0;
}
float getFixDragTrans(float delta, float viewSize, float contentSize) {
if (contentSize <= viewSize) {
return 0;
}
return delta;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
viewWidth = MeasureSpec.getSize(widthMeasureSpec);
viewHeight = MeasureSpec.getSize(heightMeasureSpec);
//
// Rescales image on rotation
//
if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight
|| viewWidth == 0 || viewHeight == 0)
return;
oldMeasuredHeight = viewHeight;
oldMeasuredWidth = viewWidth;
if (saveScale == 1) {
//Fit to screen.
float scale;
Drawable drawable = getDrawable();
if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0)
return;
int bmWidth = drawable.getIntrinsicWidth();
int bmHeight = drawable.getIntrinsicHeight();
Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);
float scaleX = (float) viewWidth / (float) bmWidth;
float scaleY = (float) viewHeight / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
// Center the image
float redundantYSpace = (float) viewHeight - (scale * (float) bmHeight);
float redundantXSpace = (float) viewWidth - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = viewWidth - 2 * redundantXSpace;
origHeight = viewHeight - 2 * redundantYSpace;
setImageMatrix(matrix);
}
fixTrans();
}
}
来源：https://stackoverflow.com/questions/20211130/how-to-zoom-in-out-with-button-click-images