Android: Add inspection & quickfix to convert findViewById to api 26

#KT-19940 Fixed Target Version 1.1.5

idea/testData/android/lint/findViewById.kt

@@ -0,0 +1,49 @@
+// INSPECTION_CLASS: org.jetbrains.kotlin.android.inspection.TypeParameterFindViewByIdInspection
+
+import android.app.Activity
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+
+@Suppress(
+        "TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER",
+        "UNUSED_VARIABLE"
+)
+class OtherActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_other)
+
+        <weak_warning descr="Can be converted to findViewById<TextView>(...)">findViewById(R.id.tvHello) as TextView</weak_warning>
+        val tvHello = <weak_warning descr="Can be converted to findViewById<TextView>(...)">findViewById(R.id.tvHello) as TextView</weak_warning>
+        val btnGo = <weak_warning descr="Can be converted to findViewById<Button>(...)">findViewById(R.id.btnGo) as Button?</weak_warning>
+
+        // should be ok, already has type parameter
+        val tvHello2 = findViewById<TextView>(R.id.tvHello) as TextView
+
+        // ok, we can't convert safe cast because semantic will be changed
+        val tvHello3 = findViewById(R.id.tvHello) as? TextView
+
+        // ok, no cast
+        foo(findViewById(R.id.tvHello))
+
+        // ok, no cast
+        findViewById(R.id.tvHello) is TextView
+    }
+
+    fun foo(view: TextView) {
+        view.text = "foo"
+    }
+}
+
+class R {
+    object layout {
+        val activity_other = 100500
+    }
+
+    object id {
+        val tvHello = 0
+        val btnGo = 1
+    }
+}

idea/testData/android/lint/viewHolder.kt

@@ -29,7 +29,7 @@ abstract class ViewHolderTest : BaseAdapter() {
             // Should use View Holder pattern here
             convertView = mInflater.<warning descr="Unconditional layout inflation from view adapter: Should use View Holder pattern (use recycled view passed into this method as the second parameter) for smoother scrolling">inflate(R.layout.your_layout, null)</warning>
 
-            val text = convertView.findViewById(R.id.text) as TextView
+            val text: TextView = convertView.findViewById(R.id.text)
             text.text = "Position " + position
 
             return convertView
@@ -46,7 +46,7 @@ abstract class ViewHolderTest : BaseAdapter() {
                 convertView = mInflater.inflate(R.layout.your_layout, null)
             }
 
-            val text = convertView!!.findViewById(R.id.text) as TextView
+            val text: TextView = convertView!!.findViewById(R.id.text)
             text.text = "Position " + position
 
             return convertView
@@ -65,7 +65,7 @@ abstract class ViewHolderTest : BaseAdapter() {
                 convertView = mInflater.inflate(R.layout.your_layout, null)
             }
 
-            val text = convertView!!.findViewById(R.id.text) as TextView
+            val text: TextView = convertView!!.findViewById(R.id.text)
             text.text = "Position " + position
 
             return convertView
@@ -80,7 +80,7 @@ abstract class ViewHolderTest : BaseAdapter() {
             // Already using View Holder pattern
             convertView = if (convertView == null) mInflater.inflate(R.layout.your_layout, null) else convertView
 
-            val text = convertView!!.findViewById(R.id.text) as TextView
+            val text: TextView = convertView!!.findViewById(R.id.text)
             text.text = "Position " + position
 
             return convertView
@@ -99,16 +99,16 @@ abstract class ViewHolderTest : BaseAdapter() {
             var v: View? = convertView
             if (v == null) v = mLayoutInflator!!.inflate(R.layout.your_layout, null)
 
-            val listItemHolder = v!!.findViewById(R.id.laptimes_list_item_holder) as LinearLayout
+            val listItemHolder: LinearLayout = v!!.findViewById(R.id.laptimes_list_item_holder)
             listItemHolder.removeAllViews()
 
             for (i in 1..5) {
-                val lapItemView = mLayoutInflator!!.inflate(R.layout.laptime_item, null)
+                val lapItemView: View  = mLayoutInflator!!.inflate(R.layout.laptime_item, null)
                 if (i == 0) {
-                    val t = lapItemView.findViewById(R.id.laptime_text) as TextView
+                    val t: TextView = lapItemView.findViewById(R.id.laptime_text)
                 }
 
-                val t2 = lapItemView.findViewById(R.id.laptime_text2) as TextView
+                val t2: TextView = lapItemView.findViewById(R.id.laptime_text2)
                 if (i < mLapTimes.size - 1 && mLapTimes.size > 1) {
                     var laptime = mLapTimes[i] - mLapTimes[i + 1]
                     if (laptime < 0) laptime = mLapTimes[i]

idea/testData/android/lintQuickfix/findViewById/nullableType.kt

@@ -0,0 +1,28 @@
+// INTENTION_TEXT: Convert cast to findViewById with type parameter
+// INSPECTION_CLASS: org.jetbrains.kotlin.android.inspection.TypeParameterFindViewByIdInspection
+
+import android.app.Activity
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+
+
+class OtherActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_other)
+
+        val tvHello = <caret>findViewById(R.id.tvHello) as TextView?
+    }
+}
+
+class R {
+    object layout {
+        val activity_other = 100500
+    }
+
+    object id {
+        val tvHello = 0
+    }
+}

idea/testData/android/lintQuickfix/findViewById/nullableType.kt.expected

@@ -0,0 +1,28 @@
+// INTENTION_TEXT: Convert cast to findViewById with type parameter
+// INSPECTION_CLASS: org.jetbrains.kotlin.android.inspection.TypeParameterFindViewByIdInspection
+
+import android.app.Activity
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+
+
+class OtherActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_other)
+
+        val tvHello = findViewById<TextView>(R.id.tvHello)
+    }
+}
+
+class R {
+    object layout {
+        val activity_other = 100500
+    }
+
+    object id {
+        val tvHello = 0
+    }
+}

idea/testData/android/lintQuickfix/findViewById/simple.kt

@@ -0,0 +1,28 @@
+// INTENTION_TEXT: Convert cast to findViewById with type parameter
+// INSPECTION_CLASS: org.jetbrains.kotlin.android.inspection.TypeParameterFindViewByIdInspection
+
+import android.app.Activity
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+
+
+class OtherActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_other)
+
+        val tvHello = <caret>findViewById(R.id.tvHello) as TextView
+    }
+}
+
+class R {
+    object layout {
+        val activity_other = 100500
+    }
+
+    object id {
+        val tvHello = 0
+    }
+}

idea/testData/android/lintQuickfix/findViewById/simple.kt.expected

@@ -0,0 +1,28 @@
+// INTENTION_TEXT: Convert cast to findViewById with type parameter
+// INSPECTION_CLASS: org.jetbrains.kotlin.android.inspection.TypeParameterFindViewByIdInspection
+
+import android.app.Activity
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+
+
+class OtherActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_other)
+
+        val tvHello = findViewById<TextView>(R.id.tvHello)
+    }
+}
+
+class R {
+    object layout {
+        val activity_other = 100500
+    }
+
+    object id {
+        val tvHello = 0
+    }
+}