限制源编辑框的最大行数,滚动到其他输入框更容易

app/src/main/java/io/legado/app/ui/widget/code/CodeView.kt

@@ -1,5 +1,6 @@
 package io.legado.app.ui.widget.code
 
+import android.annotation.SuppressLint
 import android.content.Context
 import android.graphics.Canvas
 import android.graphics.Paint
@@ -12,6 +13,7 @@ import android.text.style.BackgroundColorSpan
 import android.text.style.ForegroundColorSpan
 import android.text.style.ReplacementSpan
 import android.util.AttributeSet
+import android.view.MotionEvent
 import androidx.annotation.ColorInt
 import androidx.appcompat.widget.AppCompatMultiAutoCompleteTextView
 import java.util.*
@@ -37,6 +39,12 @@ class CodeView @JvmOverloads constructor(context: Context, attrs: AttributeSet?
     private val mSyntaxPatternMap: MutableMap<Pattern, Int> = HashMap()
     private var mIndentCharacterList = mutableListOf('{', '+', '-', '*', '/', '=')
 
+    //滑动距离的最大边界
+    private var mOffsetHeight = 0
+
+    //是否到顶或者到底的标志
+    private var mBottomFlag = false
+
     private val mUpdateRunnable = Runnable {
         val source = text
         highlightWithoutChange(source)
@@ -102,6 +110,83 @@ class CodeView @JvmOverloads constructor(context: Context, attrs: AttributeSet?
         addTextChangedListener(mEditorTextWatcher)
     }
 
+    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
+        initOffsetHeight()
+    }
+
+    override fun onTextChanged(
+        text: CharSequence,
+        start: Int,
+        lengthBefore: Int,
+        lengthAfter: Int
+    ) {
+        super.onTextChanged(text, start, lengthBefore, lengthAfter)
+        initOffsetHeight()
+    }
+
+    override fun dispatchTouchEvent(event: MotionEvent): Boolean {
+        if (event.action == MotionEvent.ACTION_DOWN) {
+            //如果是新的按下事件，则对mBottomFlag重新初始化
+            mBottomFlag = mOffsetHeight <= 0
+        }
+        return super.dispatchTouchEvent(event)
+    }
+
+    @SuppressLint("ClickableViewAccessibility")
+    override fun onTouchEvent(event: MotionEvent): Boolean {
+        val result = super.onTouchEvent(event)
+        //如果是需要拦截，则再拦截，这个方法会在onScrollChanged方法之后再调用一次
+        if (!mBottomFlag) parent.requestDisallowInterceptTouchEvent(true)
+        return result
+    }
+
+    override fun onScrollChanged(horiz: Int, vert: Int, oldHoriz: Int, oldVert: Int) {
+        super.onScrollChanged(horiz, vert, oldHoriz, oldVert)
+        if (vert == mOffsetHeight || vert == 0) {
+            //这里触发父布局或祖父布局的滑动事件
+            parent.requestDisallowInterceptTouchEvent(false)
+            mBottomFlag = true
+        }
+    }
+
+    override fun showDropDown() {
+        val screenPoint = IntArray(2)
+        getLocationOnScreen(screenPoint)
+        val displayFrame = Rect()
+        getWindowVisibleDisplayFrame(displayFrame)
+        val position = selectionStart
+        val layout = layout
+        val line = layout.getLineForOffset(position)
+        val verticalDistanceInDp = (750 + 140 * line) / displayDensity
+        dropDownVerticalOffset = verticalDistanceInDp.toInt()
+        val horizontalDistanceInDp = layout.getPrimaryHorizontal(position) / displayDensity
+        dropDownHorizontalOffset = horizontalDistanceInDp.toInt()
+        super.showDropDown()
+    }
+
+    private fun initOffsetHeight() {
+        val mLayoutHeight: Int
+
+        //获得内容面板
+        val mLayout = layout ?: return
+        //获得内容面板的高度
+        mLayoutHeight = mLayout.height
+        //获取上内边距
+        val paddingTop: Int = totalPaddingTop
+        //获取下内边距
+        val paddingBottom: Int = totalPaddingBottom
+
+        //获得控件的实际高度
+        val mHeight: Int = measuredHeight
+
+        //计算滑动距离的边界
+        mOffsetHeight = mLayoutHeight + paddingTop + paddingBottom - mHeight
+        if (mOffsetHeight <= 0) {
+            scrollTo(0, 0)
+        }
+    }
+
     private fun autoIndent(
         source: CharSequence,
         dest: Spanned,
@@ -365,21 +450,6 @@ class CodeView @JvmOverloads constructor(context: Context, attrs: AttributeSet?
         highlightWhileTextChanging = updateWhileTextChanging
     }
 
-    override fun showDropDown() {
-        val screenPoint = IntArray(2)
-        getLocationOnScreen(screenPoint)
-        val displayFrame = Rect()
-        getWindowVisibleDisplayFrame(displayFrame)
-        val position = selectionStart
-        val layout = layout
-        val line = layout.getLineForOffset(position)
-        val verticalDistanceInDp = (750 + 140 * line) / displayDensity
-        dropDownVerticalOffset = verticalDistanceInDp.toInt()
-        val horizontalDistanceInDp = layout.getPrimaryHorizontal(position) / displayDensity
-        dropDownHorizontalOffset = horizontalDistanceInDp.toInt()
-        super.showDropDown()
-    }
-
     private inner class TabWidthSpan : ReplacementSpan() {
         override fun getSize(
             paint: Paint,

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

@@ -9,6 +9,7 @@
         android:id="@+id/editText"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:inputType="textMultiLine" />
+        android:inputType="textMultiLine"
+        android:maxLines="12" />
 
 </io.legado.app.ui.widget.text.TextInputLayout>