嵌套滚动处理惯性滑动

AlexMahao · Apr 7, 2017 · cbf0c9f · cbf0c9f
1 parent fc5cdc3
commit cbf0c9f
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Showing 3 changed files with 65 additions and 8 deletions.
diff --git a/...omviewdemo/src/main/java/com/mahao/alex/customviewdemo/nestscroll/NestScrollActivity.java b/...omviewdemo/src/main/java/com/mahao/alex/customviewdemo/nestscroll/NestScrollActivity.java
@@ -3,6 +3,7 @@
 import android.graphics.Color;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
+import android.support.v4.widget.NestedScrollView;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
@@ -26,7 +27,6 @@ protected void onCreate(@Nullable Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_nest_scroll);
  mRecycleView = ((RecyclerView) findViewById(R.id.recycle));
-
  LinearLayoutManager layoutManager = new LinearLayoutManager(this);
  layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
  mRecycleView.setLayoutManager(layoutManager);

diff --git a/...ewdemo/src/main/java/com/mahao/alex/customviewdemo/nestscroll/NestScrollLinearLayout.java b/...ewdemo/src/main/java/com/mahao/alex/customviewdemo/nestscroll/NestScrollLinearLayout.java
@@ -2,19 +2,25 @@
 
 import android.content.Context;
 import android.os.Bundle;
+import android.support.v4.view.NestedScrollingParent;
 import android.support.v4.widget.SwipeRefreshLayout;
 import android.support.v7.widget.RecyclerView;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.View;
+import android.view.ViewGroup;
 import android.widget.LinearLayout;
+import android.widget.OverScroller;
+import android.widget.Scroller;
 
 /**
  * Created by mahao on 17-3-29.
  */
 
 public class NestScrollLinearLayout extends LinearLayout {
 
+ private OverScroller mScroller;
+
  public void log(String log) {
  Log.i("NestScrollLinearLayout", log);
  }
@@ -31,11 +37,12 @@ public NestScrollLinearLayout(Context context) {
  }
 
  public NestScrollLinearLayout(Context context, AttributeSet attrs) {
- super(context, attrs, 0);
+ this(context, attrs, 0);
  }
 
  public NestScrollLinearLayout(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
+ mScroller = new OverScroller(context);
  }
 
  @Override
@@ -46,12 +53,49 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 
  @Override
  public boolean onNestedFling(View target, float velocityX, float velocityY, boolean consumed) {
- return super.onNestedFling(target, velocityX, velocityY, consumed);
+ log("onNestedFling velocityY=" + velocityY);
+ // 子类滑动后
+ /* if (getScrollY() > 0 && velocityY < 0) {
+ // 向下滑动且header 隐藏，父类处理滑动
+ fling((int) velocityY);
+ return true;
+ }*/
+ return false;
  }
 
  @Override
  public boolean onNestedPreFling(View target, float velocityX, float velocityY) {
- return super.onNestedPreFling(target, velocityX, velocityY);
+ return false;
+ }
+
+ /**
+ * 处理惯性滑动
+ *
+ * @param velocityY
+ */
+ private void fling(int velocityY) {
+ mScroller.fling(0, getScrollY(), 0, velocityY, 0, 0, 0, mFirstChildHeight);
+ invalidate();
+ }
+
+ public void flingTo(int x, int y) {
+ if (y < 0) {
+ y = 0;
+ }
+ if (y > mFirstChildHeight) {
+ y = mFirstChildHeight;
+ }
+ if (y != getScrollY()) {
+ scrollTo(x, y);
+ }
+ }
+
+ @Override
+ public void computeScroll() {
+ if (mScroller.computeScrollOffset()) {
+ flingTo(0, mScroller.getCurrY());
+ invalidate();
+ }
  }
 
  @Override
@@ -72,32 +116,45 @@ public void onNestedPreScroll(View target, int dx, int dy, int[] consumed) {
  mConsumeHeight = mFirstChildHeight;
  }
  scrollTo(0, mConsumeHeight);
+ ViewGroup.LayoutParams params = getChildAt(2).getLayoutParams();
+ params.height = getChildAt(2).getMeasuredHeight() + dy;
+ log("recycleView ++++++++++++++++++++++height = " + params.height);
+ getChildAt(2).setLayoutParams(params);
  consumed[1] = dy;
  }
  }
- log("dx=" + dx + " dy=" + dy + " consumed=" + consumed[0] + " " + consumed[1]);
+ //log("dx=" + dx + " dy=" + dy + " consumed=" + consumed[0] + " " + consumed[1]);
  }
 
  @Override
  public void onNestedScroll(View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
  // 未被消费的
- if (dyUnconsumed < 0 && mConsumeHeight > 0){
+ if (dyUnconsumed < 0 && mConsumeHeight > 0) {
  mConsumeHeight = mConsumeHeight + dyUnconsumed;
  if (mConsumeHeight < 0) {
  dyUnconsumed = 0 - mConsumeHeight;
  mConsumeHeight = 0;
  }
  scrollTo(0, mConsumeHeight);
+ ViewGroup.LayoutParams params = getChildAt(2).getLayoutParams();
+ params.height = getChildAt(2).getMeasuredHeight() + dyUnconsumed;
+ log("recycleView -------------------height = " + params.height);
+ getChildAt(2).setLayoutParams(params);
  }
+
+ // 消费的和未被消息的
+
+
  // 滚动之后的回调 ，子类违背消费的
- log("dxConsumed=" + dxConsumed + " dyConsumed=" + dyConsumed + " dxUnconsumed=" + dxUnconsumed + " dyUnconsumed=" + dyUnconsumed);
+ //log("dxConsumed=" + dxConsumed + " dyConsumed=" + dyConsumed + " dxUnconsumed=" + dxUnconsumed + " dyUnconsumed=" + dyUnconsumed);
  }
 
  @Override
  public void onNestedScrollAccepted(View child, View target, int axes) {
  super.onNestedScrollAccepted(child, target, axes);
  }
 
+
  @Override
  public boolean onStartNestedScroll(View child, View target, int nestedScrollAxes) {
  return true;

diff --git a/customviewdemo/src/main/res/layout/activity_nest_scroll.xml b/customviewdemo/src/main/res/layout/activity_nest_scroll.xml
@@ -22,6 +22,6 @@
  <android.support.v7.widget.RecyclerView
  android:id="@+id/recycle"
  android:layout_width="match_parent"
- android:layout_height="match_parent"/>
+ android:layout_height="wrap_content"/>
 
 </com.mahao.alex.customviewdemo.nestscroll.NestScrollLinearLayout>