滚动视图(ScrollView)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。包括水平滚动视图(HorizontalScrollView)和垂直滚动视图(ScrollView)
隐藏滚动条
1、标签属性:android:scrollbars=”none”
2、代码设置:
setHorizontalScrollBarEnabled(false);//隐藏横向ScorollView
setVerticalScrollBarEnabled(false);//隐藏纵向ScorollView
setOnTouchListener的使用:判断ScrollView何时滑动到底部
1、getScorollY()——滚动条滑动的距离
2、getMeasuredHeight()——内容的整体高度,包括隐藏部分
3、getHeight()——显示高度。内容未布满屏幕,2=3;内容大于屏幕,3=屏幕高度,2>3。
4、getChildAt(int i)——获取ScorollView的第i个子控件
scrollTo和scrollBy:控制ScrollView视图的位置
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<!-- 横向滚动条 -->
<!-- <HorizontalScrollView
android:id="@+id/horizontalScrollView1"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:scrollbars="none" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:textSize="22sp" />
</HorizontalScrollView> -->
<!-- 纵向滚动条 -->
<Button
android:id="@+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="向上" />
<Button
android:id="@+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="向下" />
<ScrollView
android:id="@+id/scrollView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="none" >
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="22sp" />
</ScrollView>
</LinearLayout>
public class MainActivity extends Activity implements OnClickListener{
private Button button1;
private Button button2;
private TextView textView;
private ScrollView scrollView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1 = (Button) findViewById(R.id.button1);
button2 = (Button) findViewById(R.id.button2);
textView = (TextView) findViewById(R.id.textView1);
scrollView = (ScrollView) findViewById(R.id.scrollView1);
button1.setOnClickListener(this);
button2.setOnClickListener(this);
//这里是为textView赋值,内容在R.string.text中,测试时最好内容长一些,这里不再贴出。
textView.setText(getResources().getString(R.string.text));
scrollView.setOnTouchListener(new OnTouchListener() {
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
switch (event.getAction()) {
//手指抬起
case MotionEvent.ACTION_UP:
break;
//手指落下
case MotionEvent.ACTION_DOWN:
break;
//手指滑动
case MotionEvent.ACTION_MOVE:
/**
* 1、getScorollY()——滚动条滑动的距离
* 2、getMeasuredHeight()——内容的整体高度,包括隐藏部分
* 3、getHeight()——显示高度。内容未布满屏幕,2=3;内容大于屏幕,3=屏幕高度,2>3。
*/
//顶部状态
if(scrollView.getScrollY()<=0){
Log.e(">>>>>>>>>>>>>>", "顶部");
Toast.makeText(MainActivity.this, "顶部", Toast.LENGTH_SHORT).show();
}
//顶部状态
//TextView的总高度<=一屏幕的高度+滚动条的滚动距离(getChildAt(0):第0个子控件)
if(scrollView.getChildAt(0).getMeasuredHeight()<= scrollView.getScrollY() + scrollView.getHeight()){
Log.e(">>>>>>>>>>>>>>", "底部");
Toast.makeText(MainActivity.this, "底部", Toast.LENGTH_SHORT).show();
//在文本中追加内容
textView.append("111111111111111111111");
}
break;
}
return false;
}
});
}
@Override
public void onClick(View v) {
//scrollTo:以滚动视图起始位置开始计算的
//scrollBy:相对前一次的位置,滚动相应的距离
switch (v.getId()) {
case R.id.button1:
// scrollView.scrollTo(0, -30);
scrollView.scrollBy(0, -30);
break;
case R.id.button2:
// scrollView.scrollTo(0, -30);
scrollView.scrollBy(0, 30);
break;
}
}
}
HorizontalScrollView其实是FrameLayout的子类,所以内部只能有一个直接的子View。我们用来做Gallery效果,首选当然是LinearLayout,然后方向设置为水平。
1、布局文件:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<HorizontalScrollView
android:layout_width="wrap_content"
android:layout_height="150dp"
android:layout_gravity="center_vertical"
android:background="#AA444444"
android:scrollbars="none" >
<LinearLayout
android:id="@+id/id_gallery"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:orientation="horizontal" >
</LinearLayout>
</HorizontalScrollView>
</LinearLayout>
很简单,就一个HorizontalScrollView内部有个水平方向的LinearLayout
MainActivity:
public class MainActivity extends Activity
{
private LinearLayout mGallery;
private int[] mImgIds;
private LayoutInflater mInflater;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
mInflater = LayoutInflater.from(this);
initData();
initView();
}
private void initData()
{
mImgIds = new int[] { R.drawable.a, R.drawable.b, R.drawable.c,
R.drawable.d, R.drawable.e, R.drawable.f, R.drawable.g,
R.drawable.h, R.drawable.l };
}
private void initView()
{
mGallery = (LinearLayout) findViewById(R.id.id_gallery);
for (int i = 0; i < mImgIds.length; i++)
{
View view = mInflater.inflate(R.layout.activity_index_gallery_item,
mGallery, false);
ImageView img = (ImageView) view
.findViewById(R.id.id_index_gallery_item_image);
img.setImageResource(mImgIds[i]);
TextView txt = (TextView) view
.findViewById(R.id.id_index_gallery_item_text);
txt.setText("some info ");
mGallery.addView(view);
}
}
}
很简单,我预先准备了一些图片直接放在了Drawble下,然后循环加入HorizontalScrollView的LinearLayout中即可。