自動顯示與隱藏布局的ListView

效果圖

代碼

public class MainActivity extends AppCompatActivity {    private ListView listView;    String[] datas = {"A","A","A","A","A","A","A","A","A","A",            "A","A","A","A","A","A","A","A","A","A","A","A","A",};    private int scaledTouchSlop;    private float firstY = 0;    private Toolbar toolbar;    private ObjectAnimator animtor;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        toolbar = (Toolbar) findViewById(R.id.toolbar);        listView = (ListView) findViewById(R.id.listview);        //設定空的布局        initHeadView();//添加headvier要在setAdapter之前        listView.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,datas));        //判斷認為是滑動的最小距離        scaledTouchSlop = ViewConfiguration.get(this).getScaledTouchSlop();        listView.setOnTouchListener(new View.OnTouchListener() {            private float currentY;            private int direction;            private boolean mShow = true;            @Override            public boolean onTouch(View v, MotionEvent event) {                switch (event.getAction()){                    case MotionEvent.ACTION_DOWN:                        firstY = event.getY();                        break;                    case MotionEvent.ACTION_MOVE:                        currentY = event.getY();                        if(currentY - firstY >scaledTouchSlop){                            direction = 0;//向下                        }else if(firstY - currentY > scaledTouchSlop){                            direction = 1;//向上                        }                        if(direction == 1){                            if(mShow){                                toobarAnim(1);                                mShow = !mShow;                            }                        }else if(direction == 0){                            if(!mShow){                                toobarAnim(0);                                mShow = !mShow;                            }                        }                        break;                    case MotionEvent.ACTION_UP:                        break;                }                return false;//注意此處不能返回true，因為如果返回true,onTouchEvent就無法執行，導致的後果是ListView無法滑動            }        });    }    /**     * 設定頭布局，注意：這個頭布局的高度要和ToolBar的高度一致     */    public void initHeadView(){        View view = new View(this);        AbsListView.LayoutParams params = new AbsListView.LayoutParams                (AbsListView.LayoutParams.MATCH_PARENT,                        (int)getResources().getDimension(R.dimen.abc_action_bar_default_height_material));        view.setLayoutParams(params);        listView.addHeaderView(view);    }    public void toobarAnim(int direction){        //開始新的動畫之前要先取消以前的動畫        if(animtor!=null&&animtor.isRunning()){            animtor.cancel();        }        if(direction == 0){//手指向下滑動，顯示ToolBar            //toolbar.getTranslationY()擷取的是Toolbar距離自己頂部的距離            animtor = ObjectAnimator.ofFloat(toolbar, "translationY", toolbar.getTranslationY(), 0);        }else if( direction == 1){            animtor = ObjectAnimator.ofFloat(toolbar, "translationY", toolbar.getTranslationY(), -toolbar.getHeight());        }        animtor.start();    }}