add ItemChangedListener

增加位置改变时候的回调
2026-04-04 18:42:52 +08:00 · 2018-08-07 17:18:41 +08:00
parent 85de0bac5c
commit 8434f97789
7 changed files with 85 additions and 92 deletions
--- a/.idea/assetWizardSettings.xml
+++ b/.idea/assetWizardSettings.xml
@ -1,47 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="WizardSettings">
-    <option name="children">
-      <map>
-        <entry key="vectorWizard">
-          <value>
-            <PersistentState>
-              <option name="children">
-                <map>
-                  <entry key="vectorAssetStep">
-                    <value>
-                      <PersistentState>
-                        <option name="children">
-                          <map>
-                            <entry key="clipartAsset">
-                              <value>
-                                <PersistentState>
-                                  <option name="values">
-                                    <map>
-                                      <entry key="url" value="jar:file:/Applications/Android%20Studio.app/Contents/plugins/android/lib/android.jar!/images/material_design_icons/toggle/ic_star_black_24dp.xml" />
-                                    </map>
-                                  </option>
-                                </PersistentState>
-                              </value>
-                            </entry>
-                          </map>
-                        </option>
-                        <option name="values">
-                          <map>
-                            <entry key="color" value="ffffff" />
-                            <entry key="outputName" value="ic_star_black_24dp" />
-                            <entry key="sourceFile" value="$USER_HOME$" />
-                          </map>
-                        </option>
-                      </PersistentState>
-                    </value>
-                  </entry>
-                </map>
-              </option>
-            </PersistentState>
-          </value>
-        </entry>
-      </map>
-    </option>
-  </component>
-</project>
--- a/.idea/caches/build_file_checksums.ser
+++ b/.idea/caches/build_file_checksums.ser
--- a/.idea/checkstyle-idea.xml
+++ b/.idea/checkstyle-idea.xml
@ -1,17 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="CheckStyle-IDEA">
-    <option name="configuration">
-      <map>
-        <entry key="active-configuration" value="BUNDLED:(bundled):Google Checks" />
-        <entry key="checkstyle-version" value="8.7" />
-        <entry key="copy-libs" value="false" />
-        <entry key="location-0" value="BUNDLED:(bundled):Sun Checks" />
-        <entry key="location-1" value="BUNDLED:(bundled):Google Checks" />
-        <entry key="scan-before-checkin" value="false" />
-        <entry key="scanscope" value="JavaOnly" />
-        <entry key="suppress-errors" value="false" />
-      </map>
-    </option>
-  </component>
-</project>
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@ -1,5 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="CheckStyle-IDEA">
+    <option name="configuration">
+      <map>
+        <entry key="active-configuration" value="BUNDLED:(bundled):Google Checks" />
+        <entry key="checkstyle-version" value="8.7" />
+        <entry key="copy-libs" value="false" />
+        <entry key="location-0" value="BUNDLED:(bundled):Sun Checks" />
+        <entry key="location-1" value="BUNDLED:(bundled):Google Checks" />
+        <entry key="scan-before-checkin" value="false" />
+        <entry key="scanscope" value="JavaOnly" />
+        <entry key="suppress-errors" value="false" />
+      </map>
+    </option>
+  </component>
  <component name="NullableNotNullManager">
    <option name="myDefaultNullable" value="android.support.annotation.Nullable" />
    <option name="myDefaultNotNull" value="android.support.annotation.NonNull" />
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@ -2,8 +2,8 @@
 <project version="4">
  <component name="ProjectModuleManager">
    <modules>
-      <module fileurl="file://$PROJECT_DIR$/StackLayoutManager/StackLayoutManager.iml" filepath="$PROJECT_DIR$/StackLayoutManager/StackLayoutManager.iml" />
-      <module fileurl="file://$PROJECT_DIR$/StackLayoutManagerMaster.iml" filepath="$PROJECT_DIR$/StackLayoutManagerMaster.iml" />
+      <module fileurl="file://$PROJECT_DIR$/StackLayoutManager.iml" filepath="$PROJECT_DIR$/StackLayoutManager.iml" />
+      <module fileurl="file://$PROJECT_DIR$/StackLayoutManager/StackLayoutManager-StackLayoutManager.iml" filepath="$PROJECT_DIR$/StackLayoutManager/StackLayoutManager-StackLayoutManager.iml" />
      <module fileurl="file://$PROJECT_DIR$/sample/sample.iml" filepath="$PROJECT_DIR$/sample/sample.iml" />
    </modules>
  </component>
--- a/StackLayoutManager/src/main/java/com/littlemango/stacklayoutmanager/StackLayoutManager.kt
+++ b/StackLayoutManager/src/main/java/com/littlemango/stacklayoutmanager/StackLayoutManager.kt
@ -2,8 +2,7 @@ package com.littlemango.stacklayoutmanager

 import android.support.annotation.IntRange
 import android.support.v7.widget.RecyclerView
-import android.support.v7.widget.RecyclerView.SCROLL_STATE_DRAGGING
-import android.support.v7.widget.RecyclerView.SCROLL_STATE_IDLE
+import android.support.v7.widget.RecyclerView.*
 import android.view.View
 import android.view.ViewGroup

@ -41,28 +40,17 @@ class StackLayoutManager(scrollOrientation: ScrollOrientation,
    //fling的方向，用来判断是前翻还是后翻
    private var mFlingOrientation = FlingOrientation.NONE

-    init {
-        mScrollOffset = when(mScrollOrientation) {
-            ScrollOrientation.RIGHT_TO_LEFT, ScrollOrientation.BOTTOM_TO_TOP -> 0
-            else -> Int.MAX_VALUE
-        }
+    //当前所处item对应的位置
+    private var itemPosition = 0

-        if (StackAnimation::class.java.isAssignableFrom(animation)) {
-            try {
-                val cla = animation.getDeclaredConstructor(ScrollOrientation::class.java, Int::class.javaPrimitiveType)
-                mAnimation = cla.newInstance(scrollOrientation, visibleCount) as StackAnimation
-            } catch (e: Exception) {
-                e.printStackTrace()
-            }
-        }
-        if (StackLayout::class.java.isAssignableFrom(layout)) {
-            try {
-                val cla = layout.getDeclaredConstructor(ScrollOrientation::class.java, Int::class.javaPrimitiveType, Int::class.javaPrimitiveType)
-                mLayout = cla.newInstance(scrollOrientation, visibleCount, 30) as StackLayout
-            } catch (e: Exception) {
-                e.printStackTrace()
-            }
-        }
+    //判断item位置是否发生了改变
+    private var isItemPositionChanged = false
+
+    //item 位置发生改变的回调
+    private var itemChangedListener: ItemChangedListener? = null
+
+    interface ItemChangedListener {
+        fun onItemChanged(position: Int)
    }

    /**
@ -173,12 +161,43 @@ class StackLayoutManager(scrollOrientation: ScrollOrientation,
        }
    }

+    /**
+     * 设置 item 位置改变时触发的回调
+     */
+    fun setItemChangedListener(listener: ItemChangedListener) {
+        itemChangedListener = listener
+    }
+
    constructor(scrollOrientation: ScrollOrientation) : this(scrollOrientation, 3, DefaultAnimation::class.java, DefaultLayout::class.java)

    constructor(scrollOrientation: ScrollOrientation, visibleCount: Int) : this(scrollOrientation, visibleCount, DefaultAnimation::class.java, DefaultLayout::class.java)

    constructor() : this(ScrollOrientation.RIGHT_TO_LEFT)

+    init {
+        mScrollOffset = when(mScrollOrientation) {
+            ScrollOrientation.RIGHT_TO_LEFT, ScrollOrientation.BOTTOM_TO_TOP -> 0
+            else -> Int.MAX_VALUE
+        }
+
+        if (StackAnimation::class.java.isAssignableFrom(animation)) {
+            try {
+                val cla = animation.getDeclaredConstructor(ScrollOrientation::class.java, Int::class.javaPrimitiveType)
+                mAnimation = cla.newInstance(scrollOrientation, visibleCount) as StackAnimation
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+        }
+        if (StackLayout::class.java.isAssignableFrom(layout)) {
+            try {
+                val cla = layout.getDeclaredConstructor(ScrollOrientation::class.java, Int::class.javaPrimitiveType, Int::class.javaPrimitiveType)
+                mLayout = cla.newInstance(scrollOrientation, visibleCount, 30) as StackLayout
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+        }
+    }
+
    override fun generateDefaultLayoutParams(): RecyclerView.LayoutParams {
        return RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT)
@ -211,7 +230,6 @@ class StackLayoutManager(scrollOrientation: ScrollOrientation,
                            }
                        }
                    }
-
                    calculateAndScrollToTarget(view)
                }
                return mPagerMode
@ -293,6 +311,19 @@ class StackLayoutManager(scrollOrientation: ScrollOrientation,
        scrollToCenter(position, recyclerView, true)
    }

+    private fun updatePositionRecordAndNotify(position: Int) {
+        if (itemChangedListener == null) {
+            return
+        }
+        if (position != itemPosition) {
+            isItemPositionChanged = true
+            itemPosition = position
+            itemChangedListener?.onItemChanged(itemPosition)
+        } else {
+            isItemPositionChanged = false
+        }
+    }
+
    private fun handleScrollBy(offset: Int, recycler: RecyclerView.Recycler): Int {
        //期望值，不得超过最大最小值，所以期望值不一定等于实际值
        val expectOffset = mScrollOffset + offset
@ -333,6 +364,9 @@ class StackLayoutManager(scrollOrientation: ScrollOrientation,
            mAnimation?.doAnimation(movePercent, view, i - firstVisiblePosition)
        }

+        //尝试更新当前item的位置并通知外界
+        updatePositionRecordAndNotify(firstVisiblePosition)
+
        //重用
        if (firstVisiblePosition - 1 >= 0) {
            val view = recycler.getViewForPosition(firstVisiblePosition - 1)
--- a/sample/src/main/java/com/littlemango/stacklayoutmanagermaster/MainActivity.java
+++ b/sample/src/main/java/com/littlemango/stacklayoutmanagermaster/MainActivity.java
@ -31,10 +31,13 @@ public class MainActivity extends AppCompatActivity {

    private String[] selectItems;

+    private Toast mToast;
+
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
+        mToast = Toast.makeText(MainActivity.this, "", Toast.LENGTH_SHORT);
        mRecyclerView = findViewById(R.id.recycleView);

        mStackLayoutManager = new StackLayoutManager();
@ -114,12 +117,18 @@ public class MainActivity extends AppCompatActivity {
                        .show();
            }
        });
+
+        mStackLayoutManager.setItemChangedListener(new StackLayoutManager.ItemChangedListener() {
+            @Override
+            public void onItemChanged(int position) {
+                mToast.setText("first visible item position is " + position);
+                mToast.show();
+            }
+        });
    }

    class StackLayoutAdapter extends RecyclerView.Adapter<StackLayoutAdapter.StackHolder> {

-        Toast mToast = Toast.makeText(MainActivity.this, "", Toast.LENGTH_SHORT);
-
        @NonNull
        @Override
        public StackHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {