增加一屏多页（大于三页）的功能

Lionll · May 28, 2021 · 5e9a29b · 5e9a29b
1 parent 39ff0ca
commit 5e9a29b
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Showing 8 changed files with 140 additions and 34 deletions.
diff --git a/app/build.gradle b/app/build.gradle
@@ -1,4 +1,5 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion 30
@@ -30,6 +31,8 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation "androidx.core:core-ktx:+"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.recyclerview:recyclerview:1.2.0'
     implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0'

diff --git a/app/src/main/java/com/test/banner/FivePagesOneScreenTransformer.kt b/app/src/main/java/com/test/banner/FivePagesOneScreenTransformer.kt
@@ -0,0 +1,69 @@
+package com.test.banner
+
+import android.view.View
+import androidx.viewpager2.widget.ViewPager2
+
+/**
+ * 一拼五页
+ *
+ * @property scale Float
+ * @property translationX Float
+ * @constructor
+ */
+class FivePagesOneScreenTransformer(
+        private val scale: Float = DEFAULT_MIN_SCALE,
+        private val translationX: Float = -120f) : ViewPager2.PageTransformer {
+
+    companion object {
+        /**
+         * 默认的中心点
+         */
+        private const val DEFAULT_CENTER = 0.5f
+
+        /**
+         * 默认的缩放比例
+         */
+        private const val DEFAULT_MIN_SCALE = 0.85f
+    }
+
+    override fun transformPage(page: View, position: Float) {
+        val pageWidth = page.width
+        val pageHeight = page.height
+        page.pivotX = (pageWidth / 2).toFloat()
+        page.pivotY = (pageHeight / 2).toFloat()
+        when {
+            position < -2 -> {
+                // This page is way off-screen to the left.
+                page.scaleX = 0f
+                page.scaleY = 0f
+                page.pivotX = pageWidth.toFloat()
+            }
+            position < 0 -> {
+                //缩放
+                ((1 + position) * (1 - scale) + scale).also {
+                    page.scaleX = it
+                    page.scaleY = it
+                }
+                page.pivotX = pageWidth * (DEFAULT_CENTER + DEFAULT_CENTER * -position)
+                //层级
+                page.translationZ = position
+            }
+            position < 3 -> {
+                //缩放
+                ((1 - position) * (1 - scale) + scale).also {
+                    page.scaleX = it
+                    page.scaleY = it
+                }
+                page.pivotX = pageWidth * ((1 - position) * DEFAULT_CENTER)
+                //层级
+                page.translationZ = -position
+            }
+            else -> {
+                page.scaleX = 0f
+                page.scaleY = 0f
+                page.pivotX = pageWidth.toFloat()
+            }
+        }
+        page.translationX = translationX * position
+    }
+}
diff --git a/app/src/main/java/com/test/banner/ui/GalleryActivity.java b/app/src/main/java/com/test/banner/ui/GalleryActivity.java
@@ -1,21 +1,19 @@
 package com.test.banner.ui;
 
 import android.os.Bundle;
-import android.view.View;
+
+import androidx.appcompat.app.AppCompatActivity;
 
 import com.test.banner.R;
+import com.test.banner.FivePagesOneScreenTransformer;
 import com.test.banner.adapter.ImageAdapter;
-import com.test.banner.adapter.ImageNetAdapter;
 import com.test.banner.bean.DataBean;
 import com.youth.banner.Banner;
 import com.youth.banner.indicator.CircleIndicator;
 import com.youth.banner.indicator.DrawableIndicator;
-import com.youth.banner.transformer.AlphaPageTransformer;
 
-import androidx.appcompat.app.AppCompatActivity;
 import butterknife.BindView;
 import butterknife.ButterKnife;
-import butterknife.OnClick;
 
 public class GalleryActivity extends AppCompatActivity {
 
@@ -25,6 +23,8 @@ public class GalleryActivity extends AppCompatActivity {
     Banner mBanner2;
     @BindView(R.id.indicator)
     DrawableIndicator indicator;
+    @BindView(R.id.banner3)
+    Banner mBanner3;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -48,11 +48,20 @@ protected void onCreate(Bundle savedInstanceState) {
          * 魅族效果
          */
         mBanner2.setAdapter(new ImageAdapter(DataBean.getTestData()));
-        mBanner2.setIndicator(indicator,false);
+        mBanner2.setIndicator(indicator, false);
         //添加魅族效果
         mBanner2.setBannerGalleryMZ(20);
 
-
+        /**
+         * 一屏五页
+         */
+        mBanner3.setAdapter(new ImageAdapter(DataBean.getTestData()));
+        mBanner3.setIndicator(new CircleIndicator(this));
+        mBanner3.getViewPager2().setOffscreenPageLimit(4);
+        mBanner3.setIncreaseCount(8);
+        mBanner3.setPageTransformer(new FivePagesOneScreenTransformer());
+        mBanner3.setRecyclerViewPadding(350);
+        mBanner3.setCurrentItem(3);
 
     }
 

diff --git a/app/src/main/res/layout/activity_gallery.xml b/app/src/main/res/layout/activity_gallery.xml
@@ -30,4 +30,13 @@
         android:layout_gravity="center_horizontal"
         banner:normal_drawable="@drawable/indicator_normal"
         banner:selected_drawable="@drawable/indicator_selected"/>
+
+    <com.youth.banner.Banner
+        android:id="@+id/banner3"
+        android:layout_width="match_parent"
+        android:layout_height="140dp"
+        android:layout_margin="10dp"
+        banner:banner_radius="5dp"
+        banner:banner_indicator_normal_color="@android:color/white"
+        banner:banner_indicator_selected_color="@color/colorPrimary" />
 </LinearLayout>
diff --git a/banner/src/main/java/com/youth/banner/Banner.java b/banner/src/main/java/com/youth/banner/Banner.java
@@ -5,7 +5,6 @@
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
-import android.graphics.PaintFlagsDrawFilter;
 import android.graphics.Path;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffXfermode;
@@ -38,10 +37,9 @@
 import com.youth.banner.listener.OnPageChangeListener;
 import com.youth.banner.transformer.MZScaleInTransformer;
 import com.youth.banner.transformer.ScaleInTransformer;
+import com.youth.banner.util.BannerLifecycleObserver;
 import com.youth.banner.util.BannerLifecycleObserverAdapter;
 import com.youth.banner.util.BannerUtils;
-import com.youth.banner.util.BannerLifecycleObserver;
-import com.youth.banner.util.LogUtils;
 import com.youth.banner.util.ScrollSpeedManger;
 
 import java.lang.annotation.Retention;
@@ -90,6 +88,7 @@ public class Banner<T, BA extends BannerAdapter<T, ? extends RecyclerView.ViewHo
     private int indicatorMarginBottom;
     private int indicatorHeight = BannerConfig.INDICATOR_HEIGHT;
     private int indicatorRadius = BannerConfig.INDICATOR_RADIUS;
+    private int increaseCount = BannerConfig.INCREASE_COUNT;
 
     public static final int HORIZONTAL = 0;
     public static final int VERTICAL = 1;
@@ -109,7 +108,7 @@ public class Banner<T, BA extends BannerAdapter<T, ? extends RecyclerView.ViewHo
     private Paint mImagePaint;
 
     @Retention(SOURCE)
-    @IntDef( {HORIZONTAL, VERTICAL})
+    @IntDef({HORIZONTAL, VERTICAL})
     public @interface Orientation {
     }
 
@@ -391,10 +390,11 @@ public void onPageScrollStateChanged(int state) {
                 //滑动闲置或滑动结束
                 isScrolled = false;
                 if (mTempPosition != INVALID_VALUE && mIsInfiniteLoop) {
-                    if (mTempPosition == 0) {
-                        setCurrentItem(getRealCount(), false);
-                    } else if (mTempPosition == getItemCount() - 1) {
-                        setCurrentItem(1, false);
+                    int increaseCountHalf = increaseCount / 2;
+                    if (mTempPosition <= increaseCountHalf - 1) {
+                        setCurrentItem(getRealCount() + mTempPosition, false);
+                    } else if (mTempPosition >= getRealCount() + increaseCountHalf) {
+                        setCurrentItem(increaseCountHalf, false);
                     }
                 }
             }
@@ -462,7 +462,7 @@ private void setInfiniteLoop() {
         setStartPosition(isInfiniteLoop() ? mStartPosition : 0);
     }
 
-    private void setRecyclerViewPadding(int itemPadding) {
+    public void setRecyclerViewPadding(int itemPadding) {
         setRecyclerViewPadding(itemPadding, itemPadding);
     }
 
@@ -537,6 +537,7 @@ public int getRealCount() {
 
     /**
      * 是否要拦截事件
+     *
      * @param intercept
      * @return
      */
@@ -547,6 +548,7 @@ public Banner setIntercept(boolean intercept) {
 
     /**
      * 跳转到指定位置（最好在设置了数据后在调用，不然没有意义）
+     *
      * @param position
      * @return
      */
@@ -556,6 +558,7 @@ public Banner setCurrentItem(int position) {
 
     /**
      * 跳转到指定位置（最好在设置了数据后在调用，不然没有意义）
+     *
      * @param position
      * @param smoothScroll
      * @return
@@ -603,6 +606,25 @@ public Banner setUserInputEnabled(boolean enabled) {
         return this;
     }
 
+    public int getIncreaseCount() {
+        return increaseCount;
+    }
+
+    /**
+     * 设置增加的数量，适合一屏多页无限轮播
+     *
+     * @param increaseCount
+     */
+    public Banner setIncreaseCount(int increaseCount) {
+        if (increaseCount % 2 == 0) {
+            this.increaseCount = increaseCount;
+            if (getAdapter() != null) {
+                getAdapter().setIncreaseCount(increaseCount);
+            }
+        }
+        return this;
+    }
+
     /**
      * 添加PageTransformer，可以组合效果
      * {@link ViewPager2.PageTransformer}
@@ -720,12 +742,13 @@ public Banner setAdapter(BA adapter) {
 
     /**
      * 设置banner的适配器
+     *
      * @param adapter
      * @param isInfiniteLoop 是否支持无限循环
      * @return
      */
-    public Banner setAdapter(BA adapter,boolean isInfiniteLoop) {
-        mIsInfiniteLoop=isInfiniteLoop;
+    public Banner setAdapter(BA adapter, boolean isInfiniteLoop) {
+        mIsInfiniteLoop = isInfiniteLoop;
         setInfiniteLoop();
         setAdapter(adapter);
         return this;
@@ -825,7 +848,7 @@ public Banner setBannerGalleryEffect(int itemWidth, int pageMargin) {
      * @param pageMargin     页面间距,单位dp
      */
     public Banner setBannerGalleryEffect(int leftItemWidth, int rightItemWidth, int pageMargin) {
-        return setBannerGalleryEffect(leftItemWidth,rightItemWidth, pageMargin, .85f);
+        return setBannerGalleryEffect(leftItemWidth, rightItemWidth, pageMargin, .85f);
     }
 
     /**

diff --git a/banner/src/main/java/com/youth/banner/adapter/BannerAdapter.java b/banner/src/main/java/com/youth/banner/adapter/BannerAdapter.java
@@ -14,9 +14,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import androidx.annotation.NonNull;
-import androidx.recyclerview.widget.RecyclerView;
-
 
 public abstract class BannerAdapter<T, VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> implements IViewHolder<T, VH> {
     protected List<T> mDatas = new ArrayList<>();
@@ -100,7 +97,7 @@ public int getRealCount() {
     }
 
     public int getRealPosition(int position) {
-        return BannerUtils.getRealPosition(mIncreaseCount == BannerConfig.INCREASE_COUNT, position, getRealCount());
+        return BannerUtils.getRealPosition(mIncreaseCount >= 2, position, getRealCount());
     }
 
     public void setOnBannerListener(OnBannerListener<T> listener) {

diff --git a/banner/src/main/java/com/youth/banner/util/BannerUtils.java b/banner/src/main/java/com/youth/banner/util/BannerUtils.java
@@ -19,21 +19,17 @@ public class BannerUtils {
      * 获取真正的位置
      *
      * @param isIncrease 首尾是否有增加
-     * @param position  当前位置
-     * @param realCount 真实数量
+     * @param position   当前位置
+     * @param realCount  真实数量
      * @return
      */
     public static int getRealPosition(boolean isIncrease, int position, int realCount) {
-        if (!isIncrease) {
+        if (!isIncrease || realCount == 0) {
             return position;
         }
-        int realPosition;
-        if (position == 0) {
+        int realPosition = position % realCount - 1;
+        if (realPosition < 0) {
             realPosition = realCount - 1;
-        } else if (position == realCount + 1) {
-            realPosition = 0;
-        } else {
-            realPosition = position - 1;
         }
         return realPosition;
     }
@@ -68,7 +64,7 @@ public static int dp2px(float dp) {
      * @return
      */
     @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
-    public static void setBannerRound(View view,float radius) {
+    public static void setBannerRound(View view, float radius) {
         view.setOutlineProvider(new ViewOutlineProvider() {
             @Override
             public void getOutline(View view, Outline outline) {

diff --git a/build.gradle b/build.gradle
@@ -24,7 +24,7 @@ allprojects {
         maven { url "https://s01.oss.sonatype.org/content/groups/public" }
         jcenter()
         google()
-
+        mavenCentral()
     }
 }