Android - HorizontalScrollView will not scroll all the way

问题

This is bugging me for a while now, Im using HorizontalScrollView.fullScroll(HorizontalScrollView.FOCUS_RIGHT) which scrolls my ScrollView to the right, but not all the way, it's takes the scrollbar 99% percent to the right, I can manually scroll the rest of the way but for some reason it does not do it when i call the fullScroll() API.

Here's a sample code.... If you push the button a few times, the TextView will expand and you'll see the problem.

Activity: package com.example.test;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.HorizontalScrollView;
import android.widget.TextView;


public class MainActivity extends Activity {
    TextView tv;
    HorizontalScrollView hsv;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.textView1);
        hsv = (HorizontalScrollView)findViewById(R.id.horizontalScrollView1); 
    }

    public void btnOnClick(View v) {
        tv.append("a");
        hsv.fullScroll(HorizontalScrollView.FOCUS_RIGHT);       
    }
}

Layout:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <HorizontalScrollView
        android:id="@+id/horizontalScrollView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal" >

            <TextView
                android:id="@+id/textView1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="30sp"
                android:text="push the button" />

        </LinearLayout>
    </HorizontalScrollView>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="btnOnClick"
        android:text="Button" />

</LinearLayout>

回答1:

I updated your code. Replace your code with below one. Which perfectly moves HorizontalScrollView to right of the screen.

Replace Your MainActivity.java with below one:

public class AndroidHTMLActivity extends Activity{
TextView tv;
HorizontalScrollView hsv;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    tv = (TextView) findViewById(R.id.textView1);

}
public void btnOnClick(View v){

    tv.append("a");

    System.out.println("tv.getWidth()="+tv.getWidth());
    hsv = (HorizontalScrollView)findViewById(R.id.horizontalScrollView1);
    ViewTreeObserver vto = hsv.getViewTreeObserver();
    vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener(){
        @Override
        public void onGlobalLayout() {
            hsv.getViewTreeObserver().removeGlobalOnLayoutListener(this);

            hsv.scrollTo(tv.getWidth(), 0);
            }
        });


    }

}

And replace youe Xml file with below one:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" 
android:id="@+id/ll_parent_layout">
 <HorizontalScrollView
    android:id="@+id/horizontalScrollView1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" >
     <LinearLayout
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:orientation="horizontal">
         <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30dp"
            android:text="push the button" />

    </LinearLayout>
</HorizontalScrollView>

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="btnOnClick"
    android:text="Button" />

</LinearLayout>

This code fulfile your condition which you wants.

来源：https://stackoverflow.com/questions/22772632/android-horizontalscrollview-will-not-scroll-all-the-way