【发布时间】：2013-10-03 09:02:40
【问题描述】：
我在我的应用程序中使用 ViewPager 来创建用于滑动图像的滑块。一切正常，除了我必须双击缩放图像。但是双击不适用于 ViewPager。我尝试了许多解决方案但无济于事。任何帮助表示赞赏。
谢谢
【问题讨论】：
标签： android android-viewpager gesture touch-event
【发布时间】：2013-10-03 09:02:40
【问题描述】：
我来不及回答这个问题，但如果有人仍在寻找解决方案：
像这样创建一个类，只需复制粘贴代码并导入文件：
点击here
在您的 XML 中，您将 Pageradapter 的图像视图设置为执行以下操作：
<your_package_name.TouchImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</your_package_name.TouchImageView>
在您的 PagerAdapter 中不要忘记使用：
TouchImageView imageView = view.findViewById(R.id.imageView);
【讨论】：
这个解决方案非常适合我。将这些行（interface 和 onTouchEvent）添加到您的 CustomViewPager 中，如下所示：
public class CustomViewPager extends ViewPager {
//your variables
private long previousClickTime = -1;
private float x1 = -100, y1 = -100;
private VPDoubleClickListener vpDoubleClickListener;
//default build methods
public interface VPDoubleClickListener{
void onVPDoubleClicked();
}
public void setVPDoubleClickListener(VPDoubleClickListener vpDoubleClickListener){
this.vpDoubleClickListener = vpDoubleClickListener;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
long nowClick = System.currentTimeMillis();
float x2, y2;
int action = ev.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:{
x1 = ev.getX();
y1 = ev.getY();
break;
}
case MotionEvent.ACTION_UP:{
x2 = ev.getX();
y2 = ev.getY();
double space = Math.hypot(x2 - x1, y2 - y1);
//if distance of move < 25 -> ignore double tap
//300 milliseconds - double tap time threshold
if(space < 25 & nowClick - lastClick < 300){
if (vpDoubleClickListener != null) {
vpDoubleClickListener.onVPDoubleClicked();
}
Log.i("viewpager", "double tap");
}
lastClick = nowClick;
break;
}
default:break;
}
return super.onTouchEvent(ev);
}
//your custom methods
}
然后在父类中实现VPDoubleClickListener 并将setVPDoubleClickListener 设置为您的CustomViewPager，如下所示：
public class CustomActivity implements CustomViewPager.VPDoubleClickListener {
//...
VPDoubleClickListener vpDoubleClickListener = this;
@Override
public void onVPDoubleClicked() {
// Handle double tap event here!
// Handle double tap event here!
// Handle double tap event here!
// Handle double tap event here!
Log.d("TEST", "CustomViewPager double tap test.");
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_custom);
initCustomViewPager();
//...
}
private void initCustomViewPager(){
CustomViewPager customViewPager = (CustomViewPager) findViewById(R.id.customViewPager);
//...
customViewPager.setVPDoubleClickListener(vpDoubleClickListener);
}
//your custom methods
}
然后在layout.xml（在本例中为activity_custom.xml）文件中使用<com.your_username.your_app.your_package.CustomViewPager>。
抱歉有错别字。
【讨论】：
我结合了 doubleTapIsLocked 变量、dispatchTouchEvent 和 GestureDetector。这可以检测双击和滑动。
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private Boolean doubleTapIsLocked = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
ViewPager myViewPager = (ViewPager) findViewById(R.id.pager);
MyPagerAdapter myPagerAdapter = new MyPagerAdapter();
myViewPager.setAdapter(myPagerAdapter);
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if(!doubleTapIsLocked){gestureDetector.onTouchEvent(ev);}
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN://finger touching to the screen
break;
case MotionEvent.ACTION_MOVE://finger moving on the screen
break;
case MotionEvent.ACTION_UP://finger not touching to the screen
doubleTapIsLocked = false; //opens the lock
break;
}
return super.dispatchTouchEvent(ev);
}
//dedects the double tap and swipe
//////////////////////////////Gesture started///////////////////////////////////////////////////
GestureDetector.SimpleOnGestureListener simpleOnGestureListener = new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
float sensitvity = 50;//50;
float distanceX = e1.getX() - e2.getX();//horizontal distance
float distanceY = e1.getY() - e2.getY();//vertical distance
if (Math.abs(distanceY) < Math.abs(distanceX)) {//finger moving horizontaly
Log.i(TAG, "horizontal move");
doubleTapIsLocked = true;//locks double tap
}
return super.onFling(e1, e2, velocityX, velocityY);
}
@Override
public boolean onDoubleTap(MotionEvent e) {//double tap
Log.i(TAG, "onDoubleTap");
return super.onDoubleTap(e);
}
};
GestureDetector gestureDetector = new GestureDetector(simpleOnGestureListener);
//////////////////////////////Gesture end/////////////////////////////////////////////////////
【讨论】：
使用该类进行图像捏合缩放和双击缩放
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix matrix = 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;
//static NonSwipeableViewPager PagerLeft;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
static boolean b =false, c= false;
float redundantXSpace, redundantYSpace;
float width, height;
static final int CLICK = 3;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
ViewGroup vp;
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
public void setChild(ViewGroup vp) {
this.vp = vp;
}
private void sharedConstructing(Context context) {
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() {
@SuppressWarnings("deprecation")
@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];
/*Log.v("log_tag", event.getX()+" matrix "
+ x);*/
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
TouchImageView.b = false;
Log.v("event","ACTION_DOWN");
last.set(event.getX(), event.getY());
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 scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0){
TouchImageView.b = true;
Log.v("event","ACTION_MOVE scaleWidth < width y + deltaY > 0");
deltaY = -y;
}
else if (y + deltaY < -bottom){
TouchImageView.b = false;
Log.v("event","else ACTION_MOVE scaleWidth < width y + deltaY < -bottom");
deltaY = -(y + bottom);
}else{
TouchImageView.b = false;
}
} else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0){
TouchImageView.b = true;
Log.v("event","ACTION_MOVE scaleWidth < height x + deltaX > 0");
deltaX = -x;
}
else if (x + deltaX < -right){
TouchImageView.b = true;
Log.v("event","ACTION_MOVE scaleWidth < height x + deltaX < -right");
deltaX = -(x + right);
}else{
TouchImageView.b = false;
}
}else {
if (x + deltaX > 0){
TouchImageView.b = true;
Log.v("event","scaleWidth > width");
deltaX = -x;
}
else if (x + deltaX < -right){
TouchImageView.b = true;
Log.v("event","else scaleWidth > width");
deltaX = -(x + right);
}
else{
TouchImageView.b = true;
}
if (y + deltaY > 0){
TouchImageView.b = true;
Log.v("event","y + deltaY");
deltaY = -y;
}
else if (y + deltaY < -bottom){
TouchImageView.b = true;
Log.v("event","y + deltaY < -bottom");
deltaY = -(y + bottom);
}else{
TouchImageView.b = false;
}
}
/*Log.v("log_tag",height + " matrix "
+ (int) getHeightFromMatrix(matrix, TouchImageView.this));*/
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
Log.v("event","ACTION_UP");
TouchImageView.b = true;
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){
Log.v("event","ACTION_UP xDiff < CLICK && yDiff < CLICK");
performClick();
}
break;
case MotionEvent.ACTION_POINTER_UP:
//TouchImageView.b = false;
Log.v("event","ACTION_POINTER_UP");
mode = NONE;
break;
case MotionEvent.ACTION_POINTER_3_DOWN:
Log.v("event","ACTION_HOVER_MOVE");
break;
}
/*getLayoutParams().height = (int) getWidthFromMatrix(matrix,
TouchImageView.this);
getLayoutParams().width = (int) getHeightFromMatrix(matrix,
TouchImageView.this);*/
setImageMatrix(matrix);
invalidate();
return true;
}
});
}
@Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
if (bm != null) {
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;
}
@SuppressLint("NewApi")
@TargetApi(8)
@Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = (float) Math.min(
Math.max(.95f, detector.getScaleFactor()), 1.05);
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 = (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;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
/*public static void setPager(NonSwipeableViewPager pagerLeft) {
PagerLeft = pagerLeft;
}*/
}
在您的寻呼机适配器中执行此操作
TouchImageView image_view=(TouchImageView)findViewById(R.id.your_image);
【讨论】：
这很棘手，但你也可以这样做：
- 为你的视图实现 onTouch 监听器
- 为当前时间戳取一个长变量=0
- 在 onTouch 方法中检查时间差 ((variable-system.currentTimeinMili)
【讨论】：