之前也是在网上看到这种效果,不过是滚动listview来改变标题栏的颜色,感觉那个应用的比较少,比如我要滚动scrollview来实现呢,那么问题就来了,废话少说,看一下要实现的效果先(这是在项目应用的效果)。
直接上源代码:
一、核心类(ObservableScrollView.java)
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package com.jukopro.titlebarcolor;
import android.content.Context;
import android.util.AttributeSet;
import android.widget.ScrollView;
/**
* 带滚动监听的scrollview
*
*/
public class ObservableScrollView extends ScrollView {
public interface ScrollViewListener {
void onScrollChanged(ObservableScrollView scrollView, int x, int y,
int oldx, int oldy);
}
private ScrollViewListener scrollViewListener = null ;
public ObservableScrollView(Context context) {
super (context);
}
public ObservableScrollView(Context context, AttributeSet attrs,
int defStyle) {
super (context, attrs, defStyle);
}
public ObservableScrollView(Context context, AttributeSet attrs) {
super (context, attrs);
}
public void setScrollViewListener(ScrollViewListener scrollViewListener) {
this .scrollViewListener = scrollViewListener;
}
@Override
protected void onScrollChanged( int x, int y, int oldx, int oldy) {
super .onScrollChanged(x, y, oldx, oldy);
if (scrollViewListener != null ) {
scrollViewListener.onScrollChanged( this , x, y, oldx, oldy);
}
}
}
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二、具体使用(MainActivity.java)
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package com.jukopro.titlebarcolor;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.ViewTreeObserver;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import com.jukopro.titlebarcolor.ObservableScrollView.ScrollViewListener;
public class MainActivity extends Activity implements ScrollViewListener{
private ObservableScrollView scrollView;
private ListView listView;
private ImageView imageView;
private TextView textView;
private int imageHeight;
@Override
protected void onCreate(Bundle savedInstanceState) {
super .onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
scrollView = (ObservableScrollView) findViewById(R.id.scrollview);
listView = (ListView) findViewById(R.id.listview);
imageView = (ImageView) findViewById(R.id.imageview);
textView = (TextView) findViewById(R.id.textview);
initListeners();
initData();
}
private void initListeners() {
// 获取顶部图片高度后,设置滚动监听
ViewTreeObserver vto = imageView.getViewTreeObserver();
vto.addOnGlobalLayoutListener( new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
imageView.getViewTreeObserver().removeGlobalOnLayoutListener(
this );
imageHeight = imageView.getHeight();
scrollView.setScrollViewListener(MainActivity. this );
}
});
}
private void initData() {
ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity. this , android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.data));
listView.setAdapter(adapter);
}
@Override
public void onScrollChanged(ObservableScrollView scrollView, int x, int y,
int oldx, int oldy) {
// TODO Auto-generated method stub
// Log.i("TAG", "y--->" + y + " height-->" + height);
if (y <= 0 ) {
textView.setBackgroundColor(Color.argb(( int ) 0 , 227 , 29 , 26 )); //AGB由相关工具获得,或者美工提供
} else if (y > 0 && y <= imageHeight) {
float scale = ( float ) y / imageHeight;
float alpha = ( 255 * scale);
// 只是layout背景透明(仿知乎滑动效果)
textView.setBackgroundColor(Color.argb(( int ) alpha, 227 , 29 , 26 ));
} else {
textView.setBackgroundColor(Color.argb(( int ) 255 , 227 , 29 , 26 ));
}
}
}
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三、XML(activity_main.xml)
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< RelativeLayout 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"
tools:context = "${relativePackage}.${activityClass}" >
< com.jukopro.titlebarcolor.ObservableScrollView
android:id = "@+id/scrollview"
android:layout_width = "match_parent"
android:layout_height = "match_parent"
android:scrollbars = "none" >
< LinearLayout
android:layout_width = "match_parent"
android:layout_height = "wrap_content"
android:orientation = "vertical" >
< ImageView
android:id = "@+id/imageview"
android:layout_width = "match_parent"
android:layout_height = "200dp"
android:background = "@drawable/zuqiu" />
< com.jukopro.titlebarcolor.MyListview
android:id = "@+id/listview"
android:layout_width = "match_parent"
android:layout_height = "wrap_content" >
</ com.jukopro.titlebarcolor.MyListview >
</ LinearLayout >
</ com.jukopro.titlebarcolor.ObservableScrollView >
< TextView
android:id = "@+id/textview"
android:layout_width = "match_parent"
android:layout_height = "48dp"
android:gravity = "center"
android:text = "我是标题"
android:textSize = "18sp"
android:textColor = "@android:color/white"
android:background = "#00000000" />
</ RelativeLayout >
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还不懂的童鞋可以下载源代码.
以上就是这篇文章的全部内容了,希望本文的内容对大家的学习或者工作具有一定的参考学习价值,如果有疑问大家可以留言交流,谢谢大家对服务器之家的支持。
原文链接:https://blog.csdn.net/sinat_21283073/article/details/51315926