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

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