安卓自定义IOS风格的标题栏搜索框

遇到一个用iPhone的产品是一种怎样的体验？那就是不管做什么功能，遇到什么需求，安卓的效果必须要和ios一致，难受...

好吧，扯远了！今天要给大家展示的是一个IOS风格的标题栏搜索框，效果图如下：

SearchTitleBar.gif

我们先说一下实现原理。滚动列表时，通过ObjectAnimator改变搜索框的宽度来控制搜索框的展开和收回；点击搜索框打开搜索详情页面，用的安卓5.0加入共享元素转场动画。如果对转场动画不了解的同学，可以点击链接了解一下。下面我来带大家看看关键部分代码。

由于我们需要用到属性动画，而我们用到的ObjectAnimator 执行动画时需要对应属性有get set方法，因此通过 ViewWrapper 提供get set 方法封装view。

public class ViewWrapper {
    private View mTarget;

    public ViewWrapper(View target) {
        mTarget = target;
    }

    public int getWidth() {
        return mTarget.getLayoutParams().width;
    }

    public void setWidth(int width) {
        mTarget.getLayoutParams().width = width;
        mTarget.requestLayout();
    }

    public int getHeight() {
        return mTarget.getLayoutParams().height;
    }

    public void setHeight(int height) {
        mTarget.getLayoutParams().height = height;
        mTarget.requestLayout();
    }
}

然后我们自定义一个搜索框SearchTitleBar

public class SearchTitleBar extends LinearLayout implements OnLimitClickListener {
    private final int ANIM_TYPE_START = 1;
    private final int ANIM_TYPE_RESET = 2;

    @BindView(R.id.holder_view)
    View holderView;

    @BindView(R.id.search_layout)
    LinearLayout searchLayout;

    @BindView(R.id.search_tv)
    TextView searchTv;

    @BindView(R.id.search_iv)
    ImageView searchIv;

    @BindView(R.id.search_edit)
    TextView searchEt;

    @BindView(R.id.divide_view)
    View divideView;

    private OnSearchTitleBarListener onSearchTitleBarListener = null;

    private ViewWrapper wrapper = null;
    private ObjectAnimator animator = null;
    private int curAnimType = 0;

    private int holderViewWidth = 0;
    private int searchLayoutInitWidth = 0;

    public void setOnSearchTitleBarListener(OnSearchTitleBarListener onSearchTitleBarListener) {
        this.onSearchTitleBarListener = onSearchTitleBarListener;
    }

    public SearchTitleBar(Context context) {
        super(context);
        builder(context);
    }

    public SearchTitleBar(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        builder(context);
    }

    public SearchTitleBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        builder(context);
    }

    private void builder(Context context) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.search_title_bar_layout, null);
        view.setLayoutParams(new LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 1.0f));

        searchLayoutInitWidth = context.getResources().getDimensionPixelSize(R.dimen.search_init_width);

        ButterKnife.bind(this, view);

        divideView.setVisibility(View.GONE);

        wrapper = new ViewWrapper(searchLayout);

        this.addView(view);

        searchLayout.setOnClickListener(new OnLimitClickHelper(this));
    }

    public View getSearchLayout() {
        return searchLayout;
    }

    public View getSearchTv() {
        return searchTv;
    }

    public View getSearchEt() {
        return searchEt;
    }

    public View getSearchIv() {
        return searchIv;
    }

    public void setHint(String hint) {
        if (TextUtils.isEmpty(hint)) {
            searchEt.setPadding(0, 0, 0, 0);
        } else {
            searchEt.setPadding(Utils.getResourcesDimension(R.dimen.dimen_size_5), 0, 0, 0);
        }
        searchEt.setText(hint);
    }

    public void showDivide() {
        divideView.setVisibility(View.VISIBLE);
    }

    public void hideDivide() {
        divideView.setVisibility(View.GONE);
    }

    public void performAnimate(final boolean startOrReset) {
        if (holderViewWidth == 0) {
            holderViewWidth = holderView.getWidth();
        }

        int animType = 0;
        int endWidth = 0;

        if (startOrReset) {
            animType = ANIM_TYPE_START;
            endWidth = holderViewWidth;
            searchLayout.setBackgroundResource(R.drawable.shape_search_gray);
        } else {
            animType = ANIM_TYPE_RESET;
            endWidth = searchLayoutInitWidth;
            searchLayout.setBackgroundResource(R.drawable.shape_search_white);
        }

        if (curAnimType != animType) {
            if (animator != null) {
                animator.cancel();
                curAnimType = animType;
            }
        } else {
            return;
        }


        animator = ObjectAnimator.ofInt(wrapper, "width", endWidth);
        animator.addListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation) {
                hideDivide();

                if (startOrReset) {
                    setHint("输入搜索关键字");
                } else {
                    setHint("搜索");
                }
            }

            @Override
            public void onAnimationEnd(Animator animation) {
                if (curAnimType == ANIM_TYPE_START) {
                    showDivide();
                }
            }

            @Override
            public void onAnimationCancel(Animator animation) {

            }

            @Override
            public void onAnimationRepeat(Animator animation) {

            }
        });

        animator.setDuration(300);
        animator.start();
    }

    @Override
    public void onClick(View view) {
        if (view.getId() == R.id.search_layout) {
            if (onSearchTitleBarListener != null) {
                onSearchTitleBarListener.onClickSearch();
            }
        }
    }

    public interface OnSearchTitleBarListener {

        void onClickSearch();
    }
}

布局文件

这里我们定义了一个holderView，目的是通过holderView来测量搜索框展开时的宽度。

然后我们在activity中监听RecylerView的滚动来控制搜索框的展开和收回

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                setupTitleBar();
            }
        });

public void setupTitleBar() {
        if (recyclerView == null || titleBar == null) {
            return;
        }

        int top = getRvScollY();

        if(searchBarState == 0 && top >= tagetHeight){
            searchBarState = 1;
            titleBar.performAnimate(true);
        } else if((top >= tagetHeight) && (top <= resetTagetHeight)){
            titleBar.hideDivide();
        }  else if(searchBarState == 1 && top <= resetTagetHeight){
            searchBarState = 0;
            titleBar.performAnimate(false);
        }

        if (Math.abs(top) <= tagetHeight) {
            float precent = (Math.abs(top) * 1.0f / tagetHeight);
            int alpha = (int) (precent * 255);
            titleBar.setBackgroundColor(Color.argb(alpha, 255, 255, 255));
        } else {
            titleBar.setBackgroundColor(Color.argb(255, 255, 255, 255));
        }
}

public int getRvScollY() {
        LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
        int position = layoutManager.findFirstVisibleItemPosition();
        View firstVisiableChildView = layoutManager.findViewByPosition(position);
        int itemHeight = firstVisiableChildView.getHeight();
        return (position) * itemHeight - firstVisiableChildView.getTop();
}

这个地方的关键点就是我们需要获取rv滚动的距离，由于rv item是复用的，所以我们没法通过第一个可见item getTop的方法来获取滚动距离。因此我们采用的方式是获取第一个可见item的位置乘以item的高度再减去首个可见item距离顶部的距离即可获取到rv真实的滚动距离。

最后转场动画

        Intent intent = new Intent(this, SearchDetailActivity.class);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            startActivity(intent, ActivityOptions.makeSceneTransitionAnimation(this,
                    Pair.create(titleBar.getSearchLayout()
                            , Utils.getResourcesString(R.string.trans_anim_search_layout)),
                    Pair.create(titleBar.getSearchTv()
                            , Utils.getResourcesString(R.string.trans_anim_search_tv)),
                    Pair.create(titleBar.getSearchIv()
                            , Utils.getResourcesString(R.string.trans_anim_search_iv)),
                    Pair.create(titleBar.getSearchEt()
                            , Utils.getResourcesString(R.string.trans_anim_search_edit))).toBundle());
        } else {
            startActivity(intent);
        }

值得注意的是这里需要做一下版本判断，因为5.0以下的版本是不支持共享元素的。

源码请戳！