我想让飞的手势检测工作在我的Android应用程序。
我有一个GridLayout，包含9个ImageViews。来源可以在这里找到:罗曼家伙的网格布局。
我从Romain Guy的Photostream应用程序中获取的文件只做了轻微的修改。
对于简单的点击情况，我只需要为每个ImageView设置onClickListener，我添加为实现View.OnClickListener的主要活动。实现能够识别投掷的东西似乎要复杂得多。我猜这是因为它可能跨越不同的观点?
If my activity implements
OnGestureListener I don't know how to
set that as the gesture listener for
the Grid or the Image views that I
add.
public class SelectFilterActivity extends Activity implements
View.OnClickListener, OnGestureListener { ...
If my activity implements
OnTouchListener then I have no
onFling method to override (it has
two events as parameters allowing me
to determine if the fling was
noteworthy).
public class SelectFilterActivity extends Activity implements
View.OnClickListener, OnTouchListener { ...
If I make a custom View, like GestureImageView that extends ImageView I don't know how to tell the activity that a fling has occurred from the view. In any case, I tried this and the methods weren't called when I touched the screen.
我真的需要一个跨视图工作的具体例子。我应该在什么时候以及如何附加这个侦听器?我还需要能够检测单个点击。
// Gesture detection
mGestureDetector = new GestureDetector(this, new GestureDetector.SimpleOnGestureListener() {
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
int dx = (int) (e2.getX() - e1.getX());
// don't accept the fling if it's too short
// as it may conflict with a button push
if (Math.abs(dx) > MAJOR_MOVE && Math.abs(velocityX) > Math.absvelocityY)) {
if (velocityX > 0) {
moveRight();
} else {
moveLeft();
}
return true;
} else {
return false;
}
}
});
是否有可能在我的屏幕上方放置一个透明的视图来捕捉投掷?
如果我选择不从XML膨胀我的子图像视图，我可以通过手势检测器作为构造函数参数到我创建的ImageView的新子类吗?
这是一个非常简单的活动，我试图让飞动检测工作:SelectFilterActivity(改编自photostream)。
我一直在看这些资料:
检测手势-教程
SDK文档
计算器的代码
到目前为止，什么都没用，我希望能得到一些指导。
我需要一个更通用的类，我采取了Tomas的类，并添加了一个接口，发送事件到您的活动或片段。
它会在构造函数上注册监听器，所以确保你实现了接口，否则就会出现ClassCastException。该接口返回定义的四个最终整型之一
并将返回激活它的视图。
import android.app.Activity;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
public class SwipeDetector implements View.OnTouchListener{
static final int MIN_DISTANCE = 100;
private float downX, downY, upX, upY;
public final static int RIGHT_TO_LEFT=1;
public final static int LEFT_TO_RIGHT=2;
public final static int TOP_TO_BOTTOM=3;
public final static int BOTTOM_TO_TOP=4;
private View v;
private onSwipeEvent swipeEventListener;
public SwipeDetector(Activity activity,View v){
try{
swipeEventListener=(onSwipeEvent)activity;
}
catch(ClassCastException e)
{
Log.e("ClassCastException",activity.toString()+" must implement SwipeDetector.onSwipeEvent");
}
this.v=v;
}
public SwipeDetector(Fragment fragment,View v){
try{
swipeEventListener=(onSwipeEvent)fragment;
}
catch(ClassCastException e)
{
Log.e("ClassCastException",fragment.toString()+" must implement SwipeDetector.onSwipeEvent");
}
this.v=v;
}
public void onRightToLeftSwipe(){
swipeEventListener.SwipeEventDetected(v,RIGHT_TO_LEFT);
}
public void onLeftToRightSwipe(){
swipeEventListener.SwipeEventDetected(v,LEFT_TO_RIGHT);
}
public void onTopToBottomSwipe(){
swipeEventListener.SwipeEventDetected(v,TOP_TO_BOTTOM);
}
public void onBottomToTopSwipe(){
swipeEventListener.SwipeEventDetected(v,BOTTOM_TO_TOP);
}
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN: {
downX = event.getX();
downY = event.getY();
return true;
}
case MotionEvent.ACTION_UP: {
upX = event.getX();
upY = event.getY();
float deltaX = downX - upX;
float deltaY = downY - upY;
//HORIZONTAL SCROLL
if(Math.abs(deltaX) > Math.abs(deltaY))
{
if(Math.abs(deltaX) > MIN_DISTANCE){
// left or right
if(deltaX < 0)
{
this.onLeftToRightSwipe();
return true;
}
if(deltaX > 0) {
this.onRightToLeftSwipe();
return true;
}
}
else {
//not long enough swipe...
return false;
}
}
//VERTICAL SCROLL
else
{
if(Math.abs(deltaY) > MIN_DISTANCE){
// top or down
if(deltaY < 0)
{ this.onTopToBottomSwipe();
return true;
}
if(deltaY > 0)
{ this.onBottomToTopSwipe();
return true;
}
}
else {
//not long enough swipe...
return false;
}
}
return true;
}
}
return false;
}
public interface onSwipeEvent
{
public void SwipeEventDetected(View v , int SwipeType);
}
}
Thomas Fankhauser和Marek Sebera提出的我的解决方案版本(不处理垂直滑动):
SwipeInterface.java
import android.view.View;
public interface SwipeInterface {
public void onLeftToRight(View v);
public void onRightToLeft(View v);
}
ActivitySwipeDetector.java
import android.content.Context;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
public class ActivitySwipeDetector implements View.OnTouchListener {
static final String logTag = "ActivitySwipeDetector";
private SwipeInterface activity;
private float downX, downY;
private long timeDown;
private final float MIN_DISTANCE;
private final int VELOCITY;
private final float MAX_OFF_PATH;
public ActivitySwipeDetector(Context context, SwipeInterface activity){
this.activity = activity;
final ViewConfiguration vc = ViewConfiguration.get(context);
DisplayMetrics dm = context.getResources().getDisplayMetrics();
MIN_DISTANCE = vc.getScaledPagingTouchSlop() * dm.density;
VELOCITY = vc.getScaledMinimumFlingVelocity();
MAX_OFF_PATH = MIN_DISTANCE * 2;
}
public void onRightToLeftSwipe(View v){
Log.i(logTag, "RightToLeftSwipe!");
activity.onRightToLeft(v);
}
public void onLeftToRightSwipe(View v){
Log.i(logTag, "LeftToRightSwipe!");
activity.onLeftToRight(v);
}
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN: {
Log.d("onTouch", "ACTION_DOWN");
timeDown = System.currentTimeMillis();
downX = event.getX();
downY = event.getY();
return true;
}
case MotionEvent.ACTION_UP: {
Log.d("onTouch", "ACTION_UP");
long timeUp = System.currentTimeMillis();
float upX = event.getX();
float upY = event.getY();
float deltaX = downX - upX;
float absDeltaX = Math.abs(deltaX);
float deltaY = downY - upY;
float absDeltaY = Math.abs(deltaY);
long time = timeUp - timeDown;
if (absDeltaY > MAX_OFF_PATH) {
Log.i(logTag, String.format("absDeltaY=%.2f, MAX_OFF_PATH=%.2f", absDeltaY, MAX_OFF_PATH));
return v.performClick();
}
final long M_SEC = 1000;
if (absDeltaX > MIN_DISTANCE && absDeltaX > time * VELOCITY / M_SEC) {
if(deltaX < 0) { this.onLeftToRightSwipe(v); return true; }
if(deltaX > 0) { this.onRightToLeftSwipe(v); return true; }
} else {
Log.i(logTag, String.format("absDeltaX=%.2f, MIN_DISTANCE=%.2f, absDeltaX > MIN_DISTANCE=%b", absDeltaX, MIN_DISTANCE, (absDeltaX > MIN_DISTANCE)));
Log.i(logTag, String.format("absDeltaX=%.2f, time=%d, VELOCITY=%d, time*VELOCITY/M_SEC=%d, absDeltaX > time * VELOCITY / M_SEC=%b", absDeltaX, time, VELOCITY, time * VELOCITY / M_SEC, (absDeltaX > time * VELOCITY / M_SEC)));
}
}
}
return false;
}
}
我稍微修改和修复了Thomas Fankhauser的解决方案
整个系统由两个文件组成，SwipeInterface和ActivitySwipeDetector
SwipeInterface.java
import android.view.View;
public interface SwipeInterface {
public void bottom2top(View v);
public void left2right(View v);
public void right2left(View v);
public void top2bottom(View v);
}
探测器
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
public class ActivitySwipeDetector implements View.OnTouchListener {
static final String logTag = "ActivitySwipeDetector";
private SwipeInterface activity;
static final int MIN_DISTANCE = 100;
private float downX, downY, upX, upY;
public ActivitySwipeDetector(SwipeInterface activity){
this.activity = activity;
}
public void onRightToLeftSwipe(View v){
Log.i(logTag, "RightToLeftSwipe!");
activity.right2left(v);
}
public void onLeftToRightSwipe(View v){
Log.i(logTag, "LeftToRightSwipe!");
activity.left2right(v);
}
public void onTopToBottomSwipe(View v){
Log.i(logTag, "onTopToBottomSwipe!");
activity.top2bottom(v);
}
public void onBottomToTopSwipe(View v){
Log.i(logTag, "onBottomToTopSwipe!");
activity.bottom2top(v);
}
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN: {
downX = event.getX();
downY = event.getY();
return true;
}
case MotionEvent.ACTION_UP: {
upX = event.getX();
upY = event.getY();
float deltaX = downX - upX;
float deltaY = downY - upY;
// swipe horizontal?
if(Math.abs(deltaX) > MIN_DISTANCE){
// left or right
if(deltaX < 0) { this.onLeftToRightSwipe(v); return true; }
if(deltaX > 0) { this.onRightToLeftSwipe(v); return true; }
}
else {
Log.i(logTag, "Swipe was only " + Math.abs(deltaX) + " long, need at least " + MIN_DISTANCE);
}
// swipe vertical?
if(Math.abs(deltaY) > MIN_DISTANCE){
// top or down
if(deltaY < 0) { this.onTopToBottomSwipe(v); return true; }
if(deltaY > 0) { this.onBottomToTopSwipe(v); return true; }
}
else {
Log.i(logTag, "Swipe was only " + Math.abs(deltaX) + " long, need at least " + MIN_DISTANCE);
v.performClick();
}
}
}
return false;
}
}
它是这样使用的:
ActivitySwipeDetector swipe = new ActivitySwipeDetector(this);
LinearLayout swipe_layout = (LinearLayout) findViewById(R.id.swipe_layout);
swipe_layout.setOnTouchListener(swipe);
在实现Activity时，你需要实现来自SwipeInterface的方法，你可以找到在哪个视图上调用了Swipe事件。
@Override
public void left2right(View v) {
switch(v.getId()){
case R.id.swipe_layout:
// do your stuff here
break;
}
}
