使用ScrollView实现滚动效果

滚动视图是指当拥有很多内容，屏幕显示不完时，需要通过滚动来显示完整的视图

ScrollView的种类

HorizontalScrollView：水平滚动视图

ScrollView：垂直滚动视图

<?xml version="1.0" encoding="utf-8"?>

隐藏ScrollView

标签属性：android:scrollbars="none" 隐藏滚动条

代码设置：

setHorizontalScrollBarEnabled(false); 隐藏横向ScrollView

setVerticalScrollBarEnable(flase); 隐藏纵向ScrollView

水平滚动视图：直接将标签改为

setOnTouchListener的使用

判断ScrollView何时滑动到底部

public class MainActivity extends AppCompatActivity {    private TextView tv;    private ScrollView scroll;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        tv = (TextView) findViewById(R.id.content);        tv.setText(getResources().getString(R.string.content));        scroll = (ScrollView) findViewById(R.id.scroll);        scroll.setOnTouchListener(new View.OnTouchListener() {            @Override            public boolean onTouch(View v, MotionEvent event) {                switch(event.getAction()) {//                    case MotionEvent.ACTION_UP://                        break;//                    case MotionEvent.ACTION_DOWN://                        break;                    case MotionEvent.ACTION_MOVE:                        /**                         * 1.getScrollY()----滚动条滑动的距离（从0开始计算）                         * 2.getMeasuredHeight() （整个的高度）                         * 3.getHeight() （一屏的高度）                         */                        //顶部状态                        if (scroll.getScrollY() <= 0) {                            Log.i("Main", "滑动到顶部");                        }                        //底部状态                        // TextView的总高度 <= 一屏幕的高度 + 滚动条的滚动距离                        if (scroll.getChildAt(0).getMeasuredHeight() <= scroll.getHeight() + scroll.getScrollY()) {                            Log.i("Main", "滑动到底部");                            Log.i("Main", "scroll.getChildAt(0).getMeasuredHeight() = " +                                    scroll.getChildAt(0).getMeasuredHeight() +                                    "scroll.getHeight() = " + scroll.getHeight() +                                    "scroll.getScrollY() = " + scroll.getScrollY());                            tv.append(getResources().getString(R.string.content));                        }                        break;                }                return false;            }        });    }}

scrollTo和scrollBy区别

    public void scrollBy(int x, int y) {        scrollTo(mScrollX + x, mScrollY + y);    }

scrollBy记录了上一次滚动后的位置

控制ScrollView视图的位置

public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private TextView tv;    private ScrollView scroll;    private Button up_btn;    private Button down_btn;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        tv = (TextView) findViewById(R.id.content);        up_btn = (Button) findViewById(R.id.up);        down_btn = (Button) findViewById(R.id.down);        up_btn.setOnClickListener(this);        down_btn.setOnClickListener(this);        tv.setText(getResources().getString(R.string.content));        scroll = (ScrollView) findViewById(R.id.scroll);        scroll.setOnTouchListener(new View.OnTouchListener() {            @Override            public boolean onTouch(View v, MotionEvent event) {                switch(event.getAction()) {//                    case MotionEvent.ACTION_UP://                        break;//                    case MotionEvent.ACTION_DOWN://                        break;                    case MotionEvent.ACTION_MOVE:                        /**                         * 1.getScrollY()----滚动条滑动的距离（从0开始计算）                         * 2.getMeasuredHeight() （整个的高度）                         * 3.getHeight() （一屏的高度）                         */                        //顶部状态                        if (scroll.getScrollY() <= 0) {                            Log.i("Main", "滑动到顶部");                        }                        //底部状态                        // TextView的总高度 <= 一屏幕的高度 + 滚动条的滚动距离                        if (scroll.getChildAt(0).getMeasuredHeight() <= scroll.getHeight() + scroll.getScrollY()) {                            Log.i("Main", "滑动到底部");                            Log.i("Main", "scroll.getChildAt(0).getMeasuredHeight() = " +                                    scroll.getChildAt(0).getMeasuredHeight() +                                    "scroll.getHeight() = " + scroll.getHeight() +                                    "scroll.getScrollY() = " + scroll.getScrollY());                            tv.append(getResources().getString(R.string.content));                        }                        break;                }                return false;            }        });    }    @Override    public void onClick(View v) {        switch (v.getId()) {            /**             * scrollTo：以滚动视图起始位置开始计算的（所以只有第一次的点击是有效的）             * scrollBy：相对前一次的位置，去滚动对应的距离             */            case R.id.up:                scroll.scrollBy(0, -30);                break;            case R.id.down:                scroll.scrollBy(0, 30);                break;        }    }}

https://github.com/LiuchangDuan/demo

更多相关文章

随机推荐