详解Android使用CoordinatorLayout+AppBarLayout实现拉伸顶部图片功能

一、国际惯例，先看下效果图

二、不跟你多bb直接上布局文件代码

<?xml version="1.0" encoding="utf-8"? 
<LinearLayout 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=".MainActivity"
android:clipChildren="false"
android:clipToPadding="false" 
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent" 
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_behavior="com.ce.myscrollimg.AppBarLayoutOverScrollViewBehavior" 
<com.google.android.material.appbar.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll"
android:clipChildren="false"
android:clipToPadding="false" 
<com.ce.myscrollimg.DisInterceptNestedScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clipChildren="false"
android:clipToPadding="false"
app:layout_collapseMode="parallax"
app:layout_collapseParallaxMultiplier="0.8" 
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" 
<ImageView
android:id="@+id/iv_bg"
android:layout_width="match_parent"
android:layout_height="130dp"
android:src="@mipmap/ic_cover_1"
android:scaleType="centerCrop"/ 
</LinearLayout 
</com.ce.myscrollimg.DisInterceptNestedScrollView 
<com.ce.myscrollimg.DisInterceptNestedScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:tag="middle"
android:layout_marginTop="130dp" 
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" 
<View
android:layout_width="match_parent"
android:layout_height="80dp"
android:background="#FFF003"/ 
<View
android:layout_width="match_parent"
android:layout_height="80dp"
android:background="#FF3300"/ 
</LinearLayout 
</com.ce.myscrollimg.DisInterceptNestedScrollView 
<androidx.appcompat.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:tag="toolbar"
app:layout_collapseMode="pin" 
</androidx.appcompat.widget.Toolbar 
</com.google.android.material.appbar.CollapsingToolbarLayout 
</com.google.android.material.appbar.AppBarLayout 
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior" 
<com.google.android.material.tabs.TabLayout
android:id="@+id/toolbar_tab"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_gravity="center"
app:tabIndicatorColor="#FFC000"
app:tabIndicatorFullWidth="false"
app:tabIndicatorHeight="0dp"
app:tabMode="scrollable"
android:layout_marginTop="4dp"
android:layout_marginBottom="2dp"
app:tabSelectedTextColor="#FFC000"
app:tabTextColor="#FFFFFF"
app:tabMaxWidth="90dp"
app:tabPaddingEnd="-1dp" / 
<com.ce.myscrollimg.NoScrollViewPager
android:id="@+id/vp_content"
android:layout_width="match_parent"
android:layout_height="match_parent" / 
</LinearLayout 
</androidx.coordinatorlayout.widget.CoordinatorLayout 
</LinearLayout

三、上java代码

package com.ce.myscrollimg;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.viewpager.widget.ViewPager;
import android.graphics.Typeface;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import com.google.android.material.tabs.TabLayout;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private TabLayout toolbar_tab;
private NoScrollViewPager vp_content;
private ViewPagerAdapter vpAdapter;
private List<Fragment  listFragment = new ArrayList< ();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
//初始化view
private void initView(){
//tab
toolbar_tab = findViewById(R.id.toolbar_tab);
//
vp_content = findViewById(R.id.vp_content);
vpAdapter = new ViewPagerAdapter(getSupportFragmentManager(),listFragment);
vp_content.setAdapter(vpAdapter);
vp_content.setOffscreenPageLimit(2);
toolbar_tab.setupWithViewPager(vp_content);
for(int i=0;i<12;i++){
listFragment.add(CeshiFragment.newInstance("第"+i+"页"));
}
vpAdapter.notifyDataSetChanged();
for(int i=0;i<listFragment.size();i++){
TabLayout.Tab tab = toolbar_tab.getTabAt(i);
View customView = LayoutInflater.from(this).inflate(R.layout.tab_text, null, false);
TextView textView = customView.findViewById(R.id.tv_custom_tab);
//   LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
//   layoutParams.weight = 0;
//   textView.setLayoutParams(layoutParams);
if (i == 0) {
textView.setText("推荐");
} else {
textView.setText("第"+i+"页");
}
if (i == 0) {
textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
textView.setTextColor(getResources().getColor(R.color.color_FFFFC000));
} else {
textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 14);
textView.setTextColor(getResources().getColor(R.color._1E1E1E));
}
tab.setCustomView(customView);
}
toolbar_tab.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
View view = tab.getCustomView();
if (view != null) {
TextView textView = view.findViewById(R.id.tv_custom_tab);
textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
textView.setTextColor(getResources().getColor(R.color.color_FFFFC000));
}
vp_content.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
View view = tab.getCustomView();
if (view != null) {
TextView textView = view.findViewById(R.id.tv_custom_tab);
if (textView != null) {
textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 14);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
textView.setTextColor(getResources().getColor(R.color._1E1E1E));
}
}
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
}

四、重点在于设置AppBarLayout的Behavior这里自定义AppBarLayoutOverScrollViewBehavior，下面贴出代码

package com.ce.myscrollimg;
import android.animation.Animator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import androidx.appcompat.widget.Toolbar;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import androidx.core.view.ViewCompat;
import com.google.android.material.appbar.AppBarLayout;
/**
* Created by gjm on 2017/5/24.
* 目前包括的事件：
* 图片放大回弹
* 个人信息布局的top和botoom跟随图片位移
* toolbar背景变色
*/
public class AppBarLayoutOverScrollViewBehavior extends AppBarLayout.Behavior {
private static final String TAG = "overScroll";
private static final String TAG_TOOLBAR = "toolbar";
private static final String TAG_MIDDLE = "middle";
private static final float TARGET_HEIGHT = 1500;
private View mTargetView;
private int mParentHeight;
private int mTargetViewHeight;
private float mTotalDy;
private float mLastScale;
private int mLastBottom;
private boolean isAnimate;
private Toolbar mToolBar;
private ViewGroup middleLayout;//个人信息布局
private int mMiddleHeight;
private boolean isRecovering = false;//是否正在自动回弹中
private final float MAX_REFRESH_LIMIT = 0.3f;//达到这个下拉临界值就开始刷新动画
public AppBarLayoutOverScrollViewBehavior() {
}
public AppBarLayoutOverScrollViewBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onLayoutChild(CoordinatorLayout parent, AppBarLayout abl, int layoutDirection) {
boolean handled = super.onLayoutChild(parent, abl, layoutDirection);
if (mToolBar == null) {
mToolBar = parent.findViewWithTag(TAG_TOOLBAR);
}
if (middleLayout == null) {
middleLayout = (ViewGroup) parent.findViewWithTag(TAG_MIDDLE);
}
// 需要在调用过super.onLayoutChild()方法之后获取
if (mTargetView == null) {
mTargetView = parent.findViewById(R.id.iv_bg);
if (mTargetView != null) {
initial(abl);
}
}
abl.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
@Override
public final void onOffsetChanged(AppBarLayout appBarLayout, int i) {
mToolBar.setAlpha(Float.valueOf(Math.abs(i)) / Float.valueOf(appBarLayout.getTotalScrollRange()));
}
});
return handled;
}
@Override
public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child, View directTargetChild, View target, int nestedScrollAxes, int x) {
isAnimate = true;
if (target instanceof DisInterceptNestedScrollView) return true;//这个布局就是middleLayout
return super.onStartNestedScroll(parent, child, directTargetChild, target, nestedScrollAxes,x);
}
@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed, int x) {
if (!isRecovering) {
if (mTargetView != null && ((dy < 0 && child.getBottom()  = mParentHeight)
|| (dy   0 && child.getBottom()   mParentHeight))) {
scale(child, target, dy);
return;
}
}
super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed,x);
}
@Override
public boolean onNestedPreFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY) {
if (velocityY   100) {//当y速度 100,就秒弹回
isAnimate = false;
}
return super.onNestedPreFling(coordinatorLayout, child, target, velocityX, velocityY);
}
@Override
public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout abl, View target, int x) {
recovery(abl);
super.onStopNestedScroll(coordinatorLayout, abl, target,x);
}
private void initial(AppBarLayout abl) {
abl.setClipChildren(false);
mParentHeight = abl.getHeight();
mTargetViewHeight = mTargetView.getHeight();
mMiddleHeight = middleLayout.getHeight();
}
private void scale(AppBarLayout abl, View target, int dy) {
mTotalDy += -dy;
mTotalDy = Math.min(mTotalDy, TARGET_HEIGHT);
mLastScale = Math.max(1f, 1f + mTotalDy / TARGET_HEIGHT);
ViewCompat.setScaleX(mTargetView, mLastScale);
ViewCompat.setScaleY(mTargetView, mLastScale);
mLastBottom = mParentHeight + (int) (mTargetViewHeight / 2 * (mLastScale - 1));
abl.setBottom(mLastBottom);
target.setScrollY(0);
middleLayout.setTop(mLastBottom - mMiddleHeight);
middleLayout.setBottom(mLastBottom);
if (onProgressChangeListener != null) {
float progress = Math.min((mLastScale - 1) / MAX_REFRESH_LIMIT, 1);//计算0~1的进度
onProgressChangeListener.onProgressChange(progress, false);
}
}
public interface onProgressChangeListener {
/**
* 范围 0~1
*
* @param progress
* @param isRelease 是否是释放状态
*/
void onProgressChange(float progress, boolean isRelease);
}
public void setOnProgressChangeListener(AppBarLayoutOverScrollViewBehavior.onProgressChangeListener onProgressChangeListener) {
this.onProgressChangeListener = onProgressChangeListener;
}
onProgressChangeListener onProgressChangeListener;
private void recovery(final AppBarLayout abl) {
if (isRecovering) return;
if (mTotalDy   0) {
isRecovering = true;
mTotalDy = 0;
if (isAnimate) {
ValueAnimator anim = ValueAnimator.ofFloat(mLastScale, 1f).setDuration(200);
anim.addUpdateListener(
new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
float value = (float) animation.getAnimatedValue();
ViewCompat.setScaleX(mTargetView, value);
ViewCompat.setScaleY(mTargetView, value);
abl.setBottom((int) (mLastBottom - (mLastBottom - mParentHeight) * animation.getAnimatedFraction()));
middleLayout.setTop((int) (mLastBottom -
(mLastBottom - mParentHeight) * animation.getAnimatedFraction() - mMiddleHeight));
if (onProgressChangeListener != null) {
float progress = Math.min((value - 1) / MAX_REFRESH_LIMIT, 1);//计算0~1的进度
onProgressChangeListener.onProgressChange(progress, true);
}
}
}
);
anim.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
}
@Override
public void onAnimationEnd(Animator animation) {
isRecovering = false;
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
});
anim.start();
} else {
ViewCompat.setScaleX(mTargetView, 1f);
ViewCompat.setScaleY(mTargetView, 1f);
abl.setBottom(mParentHeight);
middleLayout.setTop(mParentHeight - mMiddleHeight);
//    middleLayout.setBottom(mParentHeight);
isRecovering = false;
if (onProgressChangeListener != null)
onProgressChangeListener.onProgressChange(0, true);
}
}
}
}

五、源码下载

http://xiazai.zalou.cn/201910/yuanma/MyScrollImg_jb51.rar

总结

以上所述是小编给大家介绍的Android使用CoordinatorLayout+AppBarLayout实现拉伸顶部图片功能,希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对ZaLou.Cn网站的支持！如果你觉得本文对你有帮助，欢迎转载，烦请注明出处，谢谢！