ScrollView实现滚动效果

如果长文本的内容超过一屏幕 则只能显示一屏幕的内容

设置ScrollView 通过滚动浏览下面的内容

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.lenovo.scrollview.MainActivity">

<ScrollView
android:id="@+id/scroll"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="none"><!--不显示右侧滚动条 -->

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/content"
/>

</ScrollView>

</android.support.constraint.ConstraintLayout>

package com.example.lenovo.scrollview;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.ScrollView;
import android.widget.TextView;

public class MainActivity extends Activity  {

private TextView tv;
private ScrollView scrollView;

@SuppressLint("ClickableViewAccessibility")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv=findViewById(R.id.content);
tv.setText(getResources().getString(R.string.content));

scrollView=findViewById(R.id.scroll);
//设置监听器
scrollView.setOnTouchListener(new  View.OnTouchListener() {
public boolean onTouch(View view, MotionEvent motionEvent) {
//对motionEvent的参数作判断
switch (motionEvent.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()--全长
* (3)getHeight()--一屏幕的高度
* */
//顶部状态
if(scrollView.getScrollY()<=0){
Log.i("Main","滑动到顶部");
}
//底部状态
if(scrollView.getChildAt(0).getMeasuredHeight()<=scrollView.getHeight()+scrollView.getScrollY()){
Log.i("Main","滑动到底部");
tv.append(getResources().getString(R.string.content));//滑动到底部时再次追加本篇文字
}

break;
}

}
return false;
}
});
}

}