使用过Google Play Store应用或者Google+应用的人都知道,其ActionBar能随着ListView的滑动而相应的隐藏或者显示。效果看起来很不错,为此,我笨拙的模仿了一个类似的效果,不知道有没有更好的办法。
先上主布局activity_main:
- <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
- xmlns:tools="http://schemas.android.com/tools"
- android:layout_width="match_parent"
- android:layout_height="match_parent"
- tools:context="com.beak.music.ui.MainActivity">
- <ListView
- android:id="@+id/main_list_view"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- />
- <android.support.v7.widget.Toolbar
- android:id="@+id/main_bar"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:background="@color/std_color_A"
- />
- </RelativeLayout>
现在是MainActivity.java里的代码:
- public class MainActivity extends BaseActivity{
- private static final String TAG = MainActivity.class.getSimpleName();
- private Toolbar mMainToolbar = null;
- private ListView mMainListView = null;
- private float mStartY = 0, mLastY = 0, mLastDeltaY;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- mMainToolbar = (Toolbar)this.findViewById(R.id.main_bar);
- this.setSupportActionBar(mMainToolbar);
- mMainListView = (ListView)this.findViewById(R.id.main_list_view);
- final View header = LayoutInflater.from(this).inflate(R.layout.layout_header, null);
- mMainListView.addHeaderView(header);
- mMainListView.setAdapter(new AudioAdapter(this));
- mMainListView.setOnTouchListener(new View.OnTouchListener() {
- @Override
- public boolean onTouch(View v, MotionEvent event) {
- final float y = event.getY();
- float translationY = mMainToolbar.getTranslationY();
- switch (event.getAction()) {
- case MotionEvent.ACTION_DOWN:
- // Log.v(TAG, "Down");
- mStartY = y;
- mLastY = mStartY;
- break;
- case MotionEvent.ACTION_MOVE:
- float mDeltaY = y - mLastY;
- float newTansY = translationY + mDeltaY;
- if (newTansY <= 0 && newTansY >= -mMainToolbar.getHeight()) {
- mMainToolbar.setTranslationY(newTansY);
- }
- mLastY = y;
- mLastDeltaY = mDeltaY;
- // Log.v(TAG, "Move");
- break;
- case MotionEvent.ACTION_UP:
- ObjectAnimator animator = null;
- Log.d(TAG, "mLastDeltaY=" + mLastDeltaY);
- if (mLastDeltaY < 0 && mMainListView.getFirstVisiblePosition() > 1) {
- Log.v(TAG, "listView.first=" + mMainListView.getFirstVisiblePosition());
- animator = ObjectAnimator.ofFloat(mMainToolbar, "translationY", mMainToolbar.getTranslationY(), -mMainToolbar.getHeight());
- } else {
- animator = ObjectAnimator.ofFloat(mMainToolbar, "translationY", mMainToolbar.getTranslationY(), 0);
- }
- animator.setDuration(100);
- animator.start();
- animator.setInterpolator(AnimationUtils.loadInterpolator(MainActivity.this, android.R.interpolator.linear));
- // Log.v(TAG, "Up");
- break;
- }
- return false;
- }
- });
- }
- }
一开始,先用我们自己的Toolbar替换原来的ActionBar,注意,在你的AppTheme中,windowActionbar这一项要设置为false才能用我们自己的去替换原来的,不然运行会报错,然后给Listview一个与Toolbar等高的headerView。然后再设置Touch事件的监听,
在onTouch方法的ACTION_MOVE分支中,我们计算出本次触发move事件与上次触发move或者down事件时候,我们的触发点的位置变化量-mDeltaY,然后计算出一个相应的translationY,经过与Toolbar高度比较,判断出新的translationY是否合法,合法,则用setTranslationY方法,给Toolbar赋值。
触发UP事件:
当触发了UP事件后,就要,我们就要用一个动画,来过度一下。先判断滑动方向,方向向上,则向上滑动,向下,则向下滑动。
android studio project code 代码在这里,不过是Android studio代码,没有写ADT代码
转载:http://blog.csdn.net/boybeak/article/details/41410113