Jan*_*usz 202 android zoom imageview
是否有一种常见的方法来显示大图像并使用户能够放大和缩小图像？
到现在为止我找到了两种方法:
Mik*_*tiz 206
我刚刚给TouchImageView一个新的更新.它现在包括双击缩放和Fling以及平移和缩放.下面的代码非常过时.您可以查看github项目以获取最新代码.
将TouchImageView.java放在项目中.然后它可以像ImageView一样使用.例:
TouchImageView img = (TouchImageView) findViewById(R.id.img);
如果您在xml中使用TouchImageView,则必须提供完整的包名称,因为它是自定义视图.例:
<com.example.touch.TouchImageView
android:id="@+id/img”
android:layout_width="match_parent"
android:layout_height="match_parent" />
注意:我已经删除了我之前的答案,其中包括一些非常旧的代码,现在直接链接到github上最新的代码.
如果您有兴趣将TouchImageView放入ViewPager,请参阅此答案.
Rob*_*oss 80
我调整了一些代码来创建支持多点触控(> 2.1)的TouchImageView.它的灵感来自Hello,Android这本书!(第3版)
它包含在以下3个文件中TouchImageView.java WrapMotionEvent.java EclairMotionEvent.java
TouchImageView.java
import se.robertfoss.ChanImageBrowser.Viewer;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
private static final String TAG = "Touch";
// These matrices will be used to move and zoom image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
Context context;
public TouchImageView(Context context) {
super(context);
super.setClickable(true);
this.context = context;
matrix.setTranslate(1f, 1f);
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent rawEvent) {
WrapMotionEvent event = WrapMotionEvent.wrap(rawEvent);
// Dump touch event to log
if (Viewer.isDebug == true){
dumpEvent(event);
}
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG");
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_UP:
int xDiff = (int) Math.abs(event.getX() - start.x);
int yDiff = (int) Math.abs(event.getY() - start.y);
if (xDiff < 8 && yDiff < 8){
performClick();
}
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
// ...
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);
} else if (mode == ZOOM) {
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldDist;
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
setImageMatrix(matrix);
return true; // indicate event was handled
}
});
}
public void setImage(Bitmap bm, int displayWidth, int displayHeight) {
super.setImageBitmap(bm);
//Fit to screen.
float scale;
if ((displayHeight / bm.getHeight()) >= (displayWidth / bm.getWidth())){
scale = (float)displayWidth / (float)bm.getWidth();
} else {
scale = (float)displayHeight / (float)bm.getHeight();
}
savedMatrix.set(matrix);
matrix.set(savedMatrix);
matrix.postScale(scale, scale, mid.x, mid.y);
setImageMatrix(matrix);
// Center the image
float redundantYSpace = (float)displayHeight - (scale * (float)bm.getHeight()) ;
float redundantXSpace = (float)displayWidth - (scale * (float)bm.getWidth());
redundantYSpace /= (float)2;
redundantXSpace /= (float)2;
savedMatrix.set(matrix);
matrix.set(savedMatrix);
matrix.postTranslate(redundantXSpace, redundantYSpace);
setImageMatrix(matrix);
}
/** Show an event in the LogCat view, for debugging */
private void dumpEvent(WrapMotionEvent event) {
// ...
String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new StringBuilder();
int action = event.getAction();
int actionCode = action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN
|| actionCode == MotionEvent.ACTION_POINTER_UP) {
sb.append("(pid ").append(
action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
}
sb.append("[");
for (int i = 0; i < event.getPointerCount(); i++) {
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
sb.append(")=").append((int) event.getX(i));
sb.append(",").append((int) event.getY(i));
if (i + 1 < event.getPointerCount())
sb.append(";");
}
sb.append("]");
Log.d(TAG, sb.toString());
}
/** Determine the space between the first two fingers */
private float spacing(WrapMotionEvent event) {
// ...
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
/** Calculate the mid point of the first two fingers */
private void midPoint(PointF point, WrapMotionEvent event) {
// ...
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
}
WrapMotionEvent.java
import android.view.MotionEvent;
public class WrapMotionEvent {
protected MotionEvent event;
protected WrapMotionEvent(MotionEvent event) {
this.event = event;
}
static public WrapMotionEvent wrap(MotionEvent event) {
try {
return new EclairMotionEvent(event);
} catch (VerifyError e) {
return new WrapMotionEvent(event);
}
}
public int getAction() {
return event.getAction();
}
public float getX() {
return event.getX();
}
public float getX(int pointerIndex) {
verifyPointerIndex(pointerIndex);
return getX();
}
public float getY() {
return event.getY();
}
public float getY(int pointerIndex) {
verifyPointerIndex(pointerIndex);
return getY();
}
public int getPointerCount() {
return 1;
}
public int getPointerId(int pointerIndex) {
verifyPointerIndex(pointerIndex);
return 0;
}
private void verifyPointerIndex(int pointerIndex) {
if (pointerIndex > 0) {
throw new IllegalArgumentException(
"Invalid pointer index for Donut/Cupcake");
}
}
}
EclairMotionEvent.java
import android.view.MotionEvent;
public class EclairMotionEvent extends WrapMotionEvent {
protected EclairMotionEvent(MotionEvent event) {
super(event);
}
public float getX(int pointerIndex) {
return event.getX(pointerIndex);
}
public float getY(int pointerIndex) {
return event.getY(pointerIndex);
}
public int getPointerCount() {
return event.getPointerCount();
}
public int getPointerId(int pointerIndex) {
return event.getPointerId(pointerIndex);
}
}
Jan*_*usz 60
我使用WebView并通过内存加载图像
webview.loadUrl("file://...")
WebView处理所有平移缩放和滚动.如果使用wrap_content,则webview不会大于图像,也不会显示白色区域.WebView是更好的ImageView;)
在回答Janusz的原始问题时,有几种方法可以实现这一点,所有这些方法的难易程度各不相同,并在下面说明.使用Web视图很好,但在外观和可控性方面非常有限.如果你从画布中绘制一个位图,那么最常用的解决方案似乎是MikeOrtiz,Robert Foss和/或Jacob Nordfalk所建议的.有一个很好的例子可以整合PaulBourke的android-multitouch-controller ,非常适合拥有多点触控支持和各种自定义视图.
就个人而言,如果您只是将画布绘制到位图然后在内部和ImageView中显示它并希望能够使用多点触控放大和移动,我发现MikeOrtiz的解决方案是最简单的.但是,就我的目的而言,他提供的Git代码似乎仅在他的TouchImageView自定义ImageView类是唯一的子代或者提供布局参数时才起作用:
android:layout_height="match_parent"
android:layout_height="match_parent"
不幸的是由于我的布局设计,我需要"layout_content"用于"layout_height".当我将其更改为此时,图像在底部被裁剪,我无法滚动或缩放到裁剪区域.所以我看了一下ImageView 的Source,看看Android是如何实现"onMeasure"并改变MikeOrtiz的.
@Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//**** ADDED THIS ********/////
int w = (int) bmWidth;
int h = (int) bmHeight;
width = resolveSize(w, widthMeasureSpec);
height = resolveSize(h, heightMeasureSpec);
//**** END ********///
// width = MeasureSpec.getSize(widthMeasureSpec); // REMOVED
// height = MeasureSpec.getSize(heightMeasureSpec); // REMOVED
//Fit to screen.
float scale;
float scaleX = (float)width / (float)bmWidth;
float scaleY = (float)height / (float)bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = (float)height - (scale * (float)bmHeight) ;
redundantXSpace = (float)width - (scale * (float)bmWidth);
redundantYSpace /= (float)2;
redundantXSpace /= (float)2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
// origHeight = bmHeight;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
这里resolveSize(int,int)是一个"实用程序,用于协调所需大小与MeasureSpec强加的约束,其中:
参数:
- size How big the view wants to be
- MeasureSpec Constraints imposed by the parent
返回:
- The size this view should be."
因此,在加载图像时,本质上提供的行为与原始ImageView类更相似.可以进行一些更改以支持更多种改变宽高比的屏幕.但是现在我希望这会有所帮助.感谢MikeOrtiz的原始代码,非常棒的工作.
我刚刚整合了Robert Foss的TouchImageView:开箱即用!谢谢!
我刚刚修改了一些代码,所以我可以从layout.xml中实例化它.
只需添加两个构造函数
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public TouchImageView(Context context) {
super(context);
init(context);
}
并将旧构造函数转换为init方法:
private void init(Context context){
//...old code ofconstructor of Robert Moss's code
}
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