Android 仿facebook布局效果.zip

package grimbo.android.demo.slidingmenu; import android.content.Context; import android.os.Handler; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.ViewTreeObserver.OnGlobalLayoutListener; import android.widget.HorizontalScrollView; /** * A HorizontalScrollView (HSV) implementation that disallows touch events (so no scrolling can be done by the user). * * This HSV MUST contain a single ViewGroup as its only child, and this ViewGroup will be used to display the children Views * passed in to the initViews() method. */ public class MyHorizontalScrollView extends HorizontalScrollView { public MyHorizontalScrollView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(context); } public MyHorizontalScrollView(Context context, AttributeSet attrs) { super(context, attrs); init(context); } public MyHorizontalScrollView(Context context) { super(context); init(context); } void init(Context context) { // remove the fading as the HSV looks better without it setHorizontalFadingEdgeEnabled(false); setVerticalFadingEdgeEnabled(false); } /** * @param children * The child Views to add to parent. * @param scrollToViewIdx * The index of the View to scroll to after initialisation. * @param sizeCallback * A SizeCallback to interact with the HSV. */ public void initViews(View[] children, int scrollToViewIdx, SizeCallback sizeCallback) { // A ViewGroup MUST be the only child of the HSV ViewGroup parent = (ViewGroup) getChildAt(0); // Add all the children, but add them invisible so that the layouts are calculated, but you can't see the Views for (int i = 0; i < children.length; i++) { children[i].setVisibility(View.INVISIBLE); parent.addView(children[i]); } // Add a layout listener to this HSV // This listener is responsible for arranging the child views. OnGlobalLayoutListener listener = new MyOnGlobalLayoutListener(parent, children, scrollToViewIdx, sizeCallback); getViewTreeObserver().addOnGlobalLayoutListener(listener); } @Override public boolean onTouchEvent(MotionEvent ev) { // Do not allow touch events. return false; } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { // Do not allow touch events. return false; } /** * An OnGlobalLayoutListener impl that passes on the call to onGlobalLayout to a SizeCallback, before removing all the Views * in the HSV and adding them again with calculated widths and heights. */ class MyOnGlobalLayoutListener implements OnGlobalLayoutListener { ViewGroup parent; View[] children; int scrollToViewIdx; int scrollToViewPos = 0; SizeCallback sizeCallback; /** * @param parent * The parent to which the child Views should be added. * @param children * The child Views to add to parent. * @param scrollToViewIdx * The index of the View to scroll to after initialisation. * @param sizeCallback * A SizeCallback to interact with the HSV. */ public MyOnGlobalLayoutListener(ViewGroup parent, View[] children, int scrollToViewIdx, SizeCallback sizeCallback) { this.parent = parent; this.children = children; this.scrollToViewIdx = scrollToViewIdx; this.sizeCallback = sizeCallback; } @Override public void onGlobalLayout() { // System.out.println("onGlobalLayout"); final HorizontalScrollView me = MyHorizontalScrollView.this; // The listener will remove itself as a layout listener to the HSV me.getViewTreeObserver().removeGlobalOnLayoutListener(this); // Allow the SizeCallback to 'see' the Views before we remove them and re-add them. // This lets the SizeCallback prepare View sizes, ahead of calls to SizeCallback.getViewSize(). sizeCallback.onGlobalLayout(); parent.removeViewsInLayout(0, children.length); final int w = me.getMeasuredWidth(); final int h = me.getMeasuredHeight(); // System.out.println("w=" + w + ", h=" + h); // Add each view in turn, and apply the width and height returned by the SizeCallback. int[] dims = new int[2]; scrollToViewPos = 0; for (int i = 0; i < children.length; i++) { sizeCallback.getViewSize(i, w, h, dims); // System.out.println("addView w=" + dims[0] + ", h=" + dims[1]); children[i].setVisibility(View.VISIBLE); parent.addView(children[i], dims[0], dims[1]); if (i < scrollToViewIdx) { scrollToViewPos += dims[0]; } } // For some reason we need to post this action, rather than call immediately. // If we try immediately, it will not scroll. new Handler().post(new Runnable() { @Override public void run() { me.scrollBy(scrollToViewPos, 0); } }); } } /** * Callback interface to interact with the HSV. */ public interface SizeCallback { /** * Used to allow clients to measure Views before re-adding them. */ public void onGlobalLayout(); /** * Used by clients to specify the View dimensions. * * @param idx * Index of the View. * @param w * Width of the parent View. * @param h * Height of the parent View. * @param dims * dims[0] should be set to View width. dims[1] should be set to View height. */ public void getViewSize(int idx, int w, int h, int[] dims); } }