Android群英传——第四章自动显示隐藏ActionBar/Toolbar的ListView

来源：互联网发布：淘宝名不虚传软件在哪编辑：程序博客网时间：2024/05/16 13:04
这中效果最为常见：
当ListView向上滑动的时候，Toolbar进行隐藏，当向下滑动时，Toolbar则又显示出来了。
如图
这里写图片描述
完整代码实现如下：
import android.animation.ObjectAnimator;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.Toolbar;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.view.ViewConfiguration;import android.widget.AbsListView;import android.widget.ArrayAdapter;import android.widget.ListView;public class MainActivity extends AppCompatActivity {    private Toolbar mToolbar;    private ListView mListView;    private String[] mStr = new String[20];    private int mTouchSlop;    private float mFirstY;    private float mCurrentY;    private int direction;    private ObjectAnimator mAnimator;    private boolean mShow = true;    View.OnTouchListener myTouchListener = new View.OnTouchListener() {        @Override        public boolean onTouch(View v, MotionEvent event) {            switch (event.getAction()) {                case MotionEvent.ACTION_DOWN:                    mFirstY = event.getY();                    break;                case MotionEvent.ACTION_MOVE:                    mCurrentY = event.getY();                    // 判断滑动方向                    if (mCurrentY - mFirstY > mTouchSlop) {                        direction = 0;// down                    } else if (mFirstY - mCurrentY > mTouchSlop) {                        direction = 1;// up                    }                    // 根据滑动方向播放toolbar的隐藏或者显示的动画                    if (direction == 1) {                        if (mShow) {                            toolbarAnim(1);//show                            mShow = !mShow;                        }                    } else if (direction == 0) {                        if (!mShow) {                            toolbarAnim(0);//hide                            mShow = !mShow;                        }                    }                    break;                case MotionEvent.ACTION_UP:                    break;            }            return false;        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mTouchSlop = ViewConfiguration.get(this).getScaledTouchSlop();        mToolbar = (Toolbar) findViewById(R.id.toolbar);        setSupportActionBar(mToolbar);        mListView = (ListView) findViewById(R.id.listView);        for (int i = 0; i < mStr.length; i++) {            mStr[i] = "Item " + i;        }        // 也可以使用        // (int) getResources().getDimension(R.dimen.abc_action_bar_default_height_material)方法        // 获取系统Toolbar的默认高度，但是不建议这么做，如果你要对Toolbar的高度进行定制，这个值并不能达到预期的效果        int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);        int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);        mToolbar.measure(w, h);        int toolbarHeight = mToolbar.getMeasuredHeight();        View header = new View(this);        header.setLayoutParams(new AbsListView.LayoutParams(                AbsListView.LayoutParams.MATCH_PARENT,                toolbarHeight));        Log.i("logi", "====" + getSupportActionBar().getHeight());        mListView.addHeaderView(header);        mListView.setAdapter(new ArrayAdapter<String>(                MainActivity.this,                android.R.layout.simple_expandable_list_item_1,                mStr));        mListView.setOnTouchListener(myTouchListener);    }    private void toolbarAnim(int flag) {        if (mAnimator != null && mAnimator.isRunning()) {            mAnimator.cancel();        }        if (flag == 0) {            mAnimator = ObjectAnimator.ofFloat(mToolbar,                    "translationY", mToolbar.getTranslationY(), 0);        } else {            Log.i("logi", "===height" + mToolbar.getHeight());            Log.i("logi", "===ty" + mToolbar.getTranslationY());            // 使用属性动画将y偏移            mAnimator = ObjectAnimator.ofFloat(mToolbar,                    "translationY", mToolbar.getTranslationY(),                    -mToolbar.getHeight());        }        mAnimator.start();    }}
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