fix: replace SwipeRefreshLayout's "mTarget" field to avoid content vi…

…ew becoming invisible.

Some developer will inject SwipeRefreshLayout's child view after the former is visible. After the FrameLayout is inserted, SwipeRefreshLayout still holds the wrong child reference, which will cause the FrameLayout to not be measured correctly.

app/src/main/AndroidManifest.xml

@@ -36,6 +36,7 @@
         <activity android:name=".WrapActivity" />
         <activity android:name=".ConstraintLayoutActivity" />
         <activity android:name=".SetViewActivity" />
-    </application>
+        <activity android:name=".SwipeRefreshRecyclerActivity" />
+     </application>
 
 </manifest>

app/src/main/java/com/github/nukc/sample/MainActivity.java

@@ -124,5 +124,9 @@ public void onClick(View v) {
                 startActivity(new Intent(MainActivity.this, SetViewActivity.class));
             }
         });
+
+        findViewById(R.id.btn_swipe_recycler).setOnClickListener(v -> {
+            startActivity(new Intent(MainActivity.this, SwipeRefreshRecyclerActivity.class));
+        });
     }
-}
+}

app/src/main/java/com/github/nukc/sample/SwipeRefreshRecyclerActivity.kt

@@ -0,0 +1,134 @@
+package com.github.nukc.sample
+
+import android.graphics.Color
+import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import android.util.TypedValue
+import android.view.Gravity
+import android.view.View
+import android.view.ViewGroup
+import android.widget.TextView
+import androidx.appcompat.app.AppCompatActivity
+import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.RecyclerView
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
+import com.github.nukc.stateview.StateView
+import kotlin.math.roundToInt
+
+/**
+ * a example for SwipeRefreshLayout + RecyclerView
+ */
+class SwipeRefreshRecyclerActivity: AppCompatActivity(), SwipeRefreshLayout.OnRefreshListener {
+
+    private class ViewHolderImpl(v: View): RecyclerView.ViewHolder(v)
+
+    private class Adapter: RecyclerView.Adapter<ViewHolderImpl>() {
+
+
+        private val mDataSet = ArrayList<String>()
+
+        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolderImpl {
+            val tv = TextView(parent.context)
+            tv.layoutParams = ViewGroup.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50F, parent.context.resources.displayMetrics).roundToInt()
+            )
+            tv.gravity = Gravity.CENTER
+            return ViewHolderImpl(tv)
+        }
+
+        override fun onBindViewHolder(holder: ViewHolderImpl, position: Int) {
+            val tv = holder.itemView as TextView
+            tv.text = mDataSet[position]
+        }
+
+        override fun getItemCount(): Int = mDataSet.size
+
+        fun appendDataSet(dataSet: List<String>) {
+            val from = mDataSet.size
+
+            mDataSet.addAll(dataSet)
+            notifyItemRangeInserted(from, dataSet.size)
+        }
+    }
+
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_swipe_refresh_recycler)
+
+
+        mSwipeRecyclerView = findViewById<SwipeRefreshLayout>(R.id.swipe_refresh).apply {
+            setOnRefreshListener(this@SwipeRefreshRecyclerActivity)
+        }
+
+
+        val recyclerView = findViewById<RecyclerView>(R.id.recycler_view).apply {
+            addItemDecoration(DividerItemDecoration(this@SwipeRefreshRecyclerActivity, DividerItemDecoration.HORIZONTAL))
+            adapter = mAdapter
+
+        }
+
+        // start refreshing
+        mSwipeRecyclerView.isRefreshing = true
+        onRefresh()
+
+        // important:
+        // we inject into RecyclerView after onResume()
+        // instead of onCreate(), then the bug occurred !!!
+
+        mSwipeRecyclerView.post {
+            mStateView = StateView.inject(recyclerView)
+            mStateView.onRetryClickListener = object : StateView.OnRetryClickListener {
+                override fun onRetryClick() {
+                    mSwipeRecyclerView.isRefreshing = true
+                    onRefresh()
+                }
+            }
+        }
+    }
+
+    private val mHandler = Handler(Looper.getMainLooper())
+
+    private val mAdapter = Adapter()
+
+    private lateinit var mStateView: StateView
+    private lateinit var mSwipeRecyclerView: SwipeRefreshLayout
+
+
+    override fun onDestroy() {
+        super.onDestroy()
+        mHandler.removeCallbacksAndMessages(null)
+    }
+
+    private var mStateId = 0
+
+    override fun onRefresh() {
+        // success or failure ?
+
+        if ((++mStateId and 1) == 1) {
+            // success
+            mHandler.postDelayed(1000) {
+
+                var idx = 0
+                val newDataSet = Array(10) { idx++.toString() }
+
+                mAdapter.appendDataSet(newDataSet.asList())
+                mStateView.showContent()
+                mSwipeRecyclerView.isRefreshing = false
+            }
+        }
+        else {
+            // ops :(
+            mHandler.postDelayed(1000) {
+                mStateView.showRetry()
+                mSwipeRecyclerView.isRefreshing = false
+            }
+        }
+    }
+}
+
+fun Handler.postDelayed(time: Long, action: Runnable) {
+    postDelayed(action, time)
+}

app/src/main/res/layout/activity_main.xml

@@ -109,5 +109,12 @@
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="setEmptyView" />
+
+        <Button
+            android:id="@+id/btn_swipe_recycler"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="SwipeRefreshLayout + RecyclerView" />
+
     </LinearLayout>
 </ScrollView>

app/src/main/res/layout/activity_swipe_refresh_recycler.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/swipe_refresh"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/recycler_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" />
+
+</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

kotlin/build.gradle

@@ -32,6 +32,7 @@ dependencies {
     androidTestImplementation 'androidx.test.ext:junit:1.1.2'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
     compileOnly 'androidx.constraintlayout:constraintlayout:2.0.4'
+    compileOnly 'androidx.swiperefreshlayout:swiperefreshlayout:1.0.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 }
 

kotlin/src/main/java/com/github/nukc/stateview/Injector.kt

@@ -12,6 +12,8 @@ import androidx.constraintlayout.widget.ConstraintLayout
 import androidx.core.view.NestedScrollingChild
 import androidx.core.view.NestedScrollingParent
 import androidx.core.view.ScrollingView
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
+import java.lang.Exception
 
 /**
  * @author Nukc.
@@ -24,6 +26,13 @@ internal object Injector {
         false
     }
 
+    val swipeRefreshLayoutAvailable = try {
+        Class.forName("androidx.swiperefreshlayout.widget.SwipeRefreshLayout") != null
+    }
+    catch (ignore: Throwable) {
+        false
+    }
+
     /**
      * Create a new FrameLayout (wrapper), let parent's remove children views, and add to the wrapper,
      * stateVew add to wrapper, wrapper add to parent
@@ -139,4 +148,22 @@ internal object Injector {
             stateView.stateListAnimator = target.stateListAnimator
         }
     }
+
+    /**
+     * fix bug: if someone injects SwipeRefreshLayout's child after SwipeRefreshLayout is resumed,
+     * this child will be hidden.
+     */
+    fun injectIntoSwipeRefreshLayout(layout: SwipeRefreshLayout) {
+        try {
+            val mTargetField = SwipeRefreshLayout::class.java.getDeclaredField("mTarget");
+            mTargetField.isAccessible = true
+            mTargetField.set(layout, null)
+
+            // we replace the mTarget field with 'null', then the SwipeRefreshLayout
+            // will look for it's real child again.
+        }
+        catch (e: Throwable) {
+            e.printStackTrace()
+        }
+    }
 }

kotlin/src/main/java/com/github/nukc/stateview/StateView.kt

@@ -19,6 +19,7 @@ import androidx.core.view.NestedScrollingChild
 import androidx.core.view.NestedScrollingParent
 import androidx.core.view.ScrollingView
 import androidx.core.view.ViewCompat
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
 
 /**
  * StateView is an invisible, zero-sized View that can be used
@@ -340,6 +341,12 @@ class StateView @JvmOverloads constructor(
                     ViewGroup.LayoutParams.MATCH_PARENT
                 )
                 Injector.setStateListAnimator(stateView, view)
+
+                // special for SwipeRefreshLayout
+                if (Injector.swipeRefreshLayoutAvailable && parent is SwipeRefreshLayout) {
+                    Injector.injectIntoSwipeRefreshLayout(parent)
+                }
+
                 return stateView
             }
             throw ClassCastException("view.getParent() must be ViewGroup")