开发Android主屏幕
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28-09-2019 - |
题
我的工作,有一个主屏幕的应用程序。这应该主屏幕表现得像在 Android的主屏幕在这里您可以通过在触摸屏甩手指几个视图之间切换。
该解决方案是容易的。我第3层图的实例强>,右,左和当前视图。我得到这个实例的 viewflipper 我在前面初始化。因为我有HTC G1我的筛网是320像素宽,480像素高。
假设你捕获向下运动事件一个动作的向下值时触摸屏幕。然后你移动你的手指,所以你必须重新计算视图的位置,屏幕应该在移动完全相同的方式。它的工作对我来说,到目前为止,但我现在面临一个奇怪的问题。当触摸右侧视图而无需移动您的手指,但将其保持在屏幕上小于第二视图消失,示出了左视图。
下面是我的代码:
public class MainActivity extends Activity implements OnTouchListener{
private ViewFlipper vf;
private float downXValue;
private View view1, view2, view3;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.vf = (ViewFlipper) findViewById(R.id.flipper);
if(this.vf != null){
this.view1 = vf.getChildAt(0);
this.view2 = vf.getChildAt(1);
this.view3 = vf.getChildAt(2);
vf.setDisplayedChild(0);
}
LinearLayout layMain = (LinearLayout) findViewById(R.id.layout_main);
layMain.setOnTouchListener((OnTouchListener) this);
}
public boolean onTouch(View v, MotionEvent arg1) {
final View currentView = vf.getCurrentView();
final View leftView, rightView;
if(currentView == view1){
leftView = view3;
rightView = view2;
}else if(currentView == view2){
leftView = view1;
rightView = view3;
}else if(currentView == view3){
leftView = view2;
rightView = view1;
}else{
leftView = null;
rightView = null;
}
switch (arg1.getAction()){
case MotionEvent.ACTION_DOWN:{
this.downXValue = arg1.getX();
break;
}
case MotionEvent.ACTION_UP:{
float currentX = arg1.getX();
if ((downXValue < currentX)){
if(currentView != view3){
float t3 = (320-(currentX-downXValue))/320;
this.vf.setInAnimation(AnimationHelper.inFromLeftAnimation(t3));
this.vf.setOutAnimation(AnimationHelper.outToRightAnimation(t3));
this.vf.showPrevious(); }
}
if ((downXValue > currentX)){
if(currentView != view2){
float t = (320-(downXValue-currentX))/320;
this.vf.setInAnimation(AnimationHelper.inFromRightAnimation(t));
this.vf.setOutAnimation(AnimationHelper.outToLeftAnimation(t));
this.vf.showNext();}
}
}
break;
case MotionEvent.ACTION_MOVE:{
leftView.setVisibility(View.VISIBLE);
rightView.setVisibility(View.VISIBLE);
float currentX = arg1.getX();
if(downXValue > currentX){
if(currentView != view2){
currentView.layout((int) (currentX - downXValue),
currentView.getTop(),
(int) (currentX - downXValue) + 320,
currentView.getBottom());
}
}
if(downXValue < currentX){
if(currentView != view3){
currentView.layout((int) (currentX - downXValue),
currentView.getTop(),
(int) (currentX - downXValue) + 320,
currentView.getBottom());
}
}
leftView.layout(currentView.getLeft()-320, leftView.getTop(),
currentView.getLeft(), leftView.getBottom());
rightView.layout(currentView.getRight(), rightView.getTop(),
currentView.getRight() + 320, rightView.getBottom());
}
}
return true;
}
public static class AnimationHelper {
public static Animation inFromRightAnimation(float param) {
Animation inFromRight = new TranslateAnimation(
Animation.RELATIVE_TO_PARENT, +param,
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, 0.0f);
inFromRight.setDuration(250);
inFromRight.setInterpolator(new AccelerateInterpolator());
return inFromRight;
}
public static Animation outToLeftAnimation(float param) {
Animation outtoLeft = new TranslateAnimation(
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, -param,
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, 0.0f);
outtoLeft.setDuration(250);
outtoLeft.setInterpolator(new AccelerateInterpolator());
return outtoLeft;
}
// for the next movement
public static Animation inFromLeftAnimation(float param) {
Animation inFromLeft = new TranslateAnimation(
Animation.RELATIVE_TO_PARENT, -param,
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, 0.0f);
inFromLeft.setDuration(250);
inFromLeft.setInterpolator(new AccelerateInterpolator());
return inFromLeft;
}
public static Animation outToRightAnimation(float param) {
Animation outtoRight = new TranslateAnimation(
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, +param,
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, 0.0f);
outtoRight.setDuration(250);
outtoRight.setInterpolator(new AccelerateInterpolator());
return outtoRight;
}
}
}
我觉得这样的主屏幕是一个有趣的UI元素。
任何想法?
解决方案
修改强>(2012年7月3日):
由于似乎仍对这个答案了不少意见和建议,我想我应该添加备注,与较新的SDK,您现在应该使用的 ViewPager 的代替,以具有相同的功能。那类也包括在支持Android库,帮助您还用它来运行在早期Android设备。
修改强>(2013年3月4日):
由于还有人来这里,就是想也说我把一个ViewPager与背景在较慢的速度移动给视差效果。该代码是此处。
如果你真的想都做手工,原来答案就在这里...以下
我认为你可以找到你在找什么在这里: HTTP://www.anddev。组织/ why_do_not_these_codes_work-t4012.html
我曾经在不同的项目中也创建一个主屏幕,不同的看法。这是直接从Android启动,它工作得非常好以下线程之后。
下面是我的代码...第一源代码
package com.matthieu.launcher;
import android.content.Context;
import android.util.Log;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewConfiguration;
import android.widget.Scroller;
public class DragableSpace extends ViewGroup {
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private int mScrollX = 0;
private int mCurrentScreen = 0;
private float mLastMotionX;
private static final String LOG_TAG = "DragableSpace";
private static final int SNAP_VELOCITY = 1000;
private final static int TOUCH_STATE_REST = 0;
private final static int TOUCH_STATE_SCROLLING = 1;
private int mTouchState = TOUCH_STATE_REST;
private int mTouchSlop = 0;
public DragableSpace(Context context) {
super(context);
mScroller = new Scroller(context);
mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
this.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.FILL_PARENT));
}
public DragableSpace(Context context, AttributeSet attrs) {
super(context, attrs);
mScroller = new Scroller(context);
mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
this.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT ,
ViewGroup.LayoutParams.FILL_PARENT));
TypedArray a=getContext().obtainStyledAttributes(attrs,R.styleable.DragableSpace);
mCurrentScreen = a.getInteger(R.styleable.DragableSpace_default_screen, 0);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
/*
* This method JUST determines whether we want to intercept the motion.
* If we return true, onTouchEvent will be called and we do the actual
* scrolling there.
*/
/*
* Shortcut the most recurring case: the user is in the dragging state
* and he is moving his finger. We want to intercept this motion.
*/
final int action = ev.getAction();
if ((action == MotionEvent.ACTION_MOVE)
&& (mTouchState != TOUCH_STATE_REST)) {
return true;
}
final float x = ev.getX();
switch (action) {
case MotionEvent.ACTION_MOVE:
/*
* mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
* whether the user has moved far enough from his original down touch.
*/
/*
* Locally do absolute value. mLastMotionX is set to the y value
* of the down event.
*/
final int xDiff = (int) Math.abs(x - mLastMotionX);
boolean xMoved = xDiff > mTouchSlop;
if (xMoved) {
// Scroll if the user moved far enough along the X axis
mTouchState = TOUCH_STATE_SCROLLING;
}
break;
case MotionEvent.ACTION_DOWN:
// Remember location of down touch
mLastMotionX = x;
/*
* If being flinged and user touches the screen, initiate drag;
* otherwise don't. mScroller.isFinished should be false when
* being flinged.
*/
mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING;
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
// Release the drag
mTouchState = TOUCH_STATE_REST;
break;
}
/*
* The only time we want to intercept motion events is if we are in the
* drag mode.
*/
return mTouchState != TOUCH_STATE_REST;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
final int action = event.getAction();
final float x = event.getX();
switch (action) {
case MotionEvent.ACTION_DOWN:
Log.i(LOG_TAG, "event : down");
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
// Remember where the motion event started
mLastMotionX = x;
break;
case MotionEvent.ACTION_MOVE:
// Log.i(LOG_TAG,"event : move");
// if (mTouchState == TOUCH_STATE_SCROLLING) {
// Scroll to follow the motion event
final int deltaX = (int) (mLastMotionX - x);
mLastMotionX = x;
//Log.i(LOG_TAG, "event : move, deltaX " + deltaX + ", mScrollX " + mScrollX);
if (deltaX < 0) {
if (mScrollX > 0) {
scrollBy(Math.max(-mScrollX, deltaX), 0);
}
} else if (deltaX > 0) {
final int availableToScroll = getChildAt(getChildCount() - 1)
.getRight()
- mScrollX - getWidth();
if (availableToScroll > 0) {
scrollBy(Math.min(availableToScroll, deltaX), 0);
}
}
// }
break;
case MotionEvent.ACTION_UP:
Log.i(LOG_TAG, "event : up");
// if (mTouchState == TOUCH_STATE_SCROLLING) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000);
int velocityX = (int) velocityTracker.getXVelocity();
if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) {
// Fling hard enough to move left
snapToScreen(mCurrentScreen - 1);
} else if (velocityX < -SNAP_VELOCITY
&& mCurrentScreen < getChildCount() - 1) {
// Fling hard enough to move right
snapToScreen(mCurrentScreen + 1);
} else {
snapToDestination();
}
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
// }
mTouchState = TOUCH_STATE_REST;
break;
case MotionEvent.ACTION_CANCEL:
Log.i(LOG_TAG, "event : cancel");
mTouchState = TOUCH_STATE_REST;
}
mScrollX = this.getScrollX();
return true;
}
private void snapToDestination() {
final int screenWidth = getWidth();
final int whichScreen = (mScrollX + (screenWidth / 2)) / screenWidth;
Log.i(LOG_TAG, "from des");
snapToScreen(whichScreen);
}
public void snapToScreen(int whichScreen) {
Log.i(LOG_TAG, "snap To Screen " + whichScreen);
mCurrentScreen = whichScreen;
final int newX = whichScreen * getWidth();
final int delta = newX - mScrollX;
mScroller.startScroll(mScrollX, 0, delta, 0, Math.abs(delta) * 2);
invalidate();
}
public void setToScreen(int whichScreen) {
Log.i(LOG_TAG, "set To Screen " + whichScreen);
mCurrentScreen = whichScreen;
final int newX = whichScreen * getWidth();
mScroller.startScroll(newX, 0, 0, 0, 10);
invalidate();
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int childLeft = 0;
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
final int childWidth = child.getMeasuredWidth();
child.layout(childLeft, 0, childLeft + childWidth, child
.getMeasuredHeight());
childLeft += childWidth;
}
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
final int width = MeasureSpec.getSize(widthMeasureSpec);
final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
if (widthMode != MeasureSpec.EXACTLY) {
throw new IllegalStateException("error mode.");
}
final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
if (heightMode != MeasureSpec.EXACTLY) {
throw new IllegalStateException("error mode.");
}
// The children are given the same width and height as the workspace
final int count = getChildCount();
for (int i = 0; i < count; i++) {
getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
}
Log.i(LOG_TAG, "moving to screen "+mCurrentScreen);
scrollTo(mCurrentScreen * width, 0);
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
mScrollX = mScroller.getCurrX();
scrollTo(mScrollX, 0);
postInvalidate();
}
}
}
和布局文件:
<?xml version="1.0" encoding="utf-8"?>
<com.matthieu.launcher.DragableSpace xmlns:app="http://schemas.android.com/apk/res/com.matthieu.launcher"
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/space"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
app:default_screen="1"
>
<include android:id="@+id/left" layout="@layout/left_screen" />
<include android:id="@+id/center" layout="@layout/initial_screen" />
<include android:id="@+id/right" layout="@layout/right_screen" />
</com.matthieu.launcher.DragableSpace>
要能够在XML文件中的额外属性,要保存这个在res /价值/ attrs.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="DragableSpace">
<attr name="default_screen" format="integer"/>
</declare-styleable>
</resources>
其他提示
马蒂厄的代码是很不错的,但方向改变之后它不保存状态。为了解决这个问题,下面的代码添加到DragableSpace类
/**
* Return the parceable instance to be saved
*/
@Override
protected Parcelable onSaveInstanceState() {
final SavedState state = new SavedState(super.onSaveInstanceState());
state.currentScreen = mCurrentScreen;
return state;
}
/**
* Restore the previous saved current screen
*/
@Override
protected void onRestoreInstanceState(Parcelable state) {
SavedState savedState = (SavedState) state;
super.onRestoreInstanceState(savedState.getSuperState());
if (savedState.currentScreen != -1) {
mCurrentScreen = savedState.currentScreen;
}
}
// ========================= INNER CLASSES ==============================
public interface onViewChangedEvent{
void onViewChange (int currentViewIndex);
}
/**
* A SavedState which save and load the current screen
*/
public static class SavedState extends BaseSavedState {
int currentScreen = -1;
/**
* Internal constructor
*
* @param superState
*/
SavedState(Parcelable superState) {
super(superState);
}
/**
* Private constructor
*
* @param in
*/
private SavedState(Parcel in) {
super(in);
currentScreen = in.readInt();
}
/**
* Save the current screen
*/
@Override
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeInt(currentScreen);
}
/**
* Return a Parcelable creator
*/
public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
我已经从Kevin的回答取它。