Fix the issue of committing text with newCursorPosition=0

Fix the issue that cusor is incorrectly positioned with the following
API:
  - commitText(text, 0)
  - setComposingText(text, 0)

Bug: 21476564
Bug: 240359838
Fix: 21476564
Test: atest FrameworksCoreTests:BaseInputConnectionTest

Change-Id: I537dc384deffaf74f38bbd158e0f433ca67fa047

core/java/android/view/inputmethod/BaseInputConnection.java

@@ -237,7 +237,7 @@ public class BaseInputConnection implements InputConnection {
      */
     @Override
     public boolean commitText(CharSequence text, int newCursorPosition) {
-        if (DEBUG) Log.v(TAG, "commitText " + text);
+        if (DEBUG) Log.v(TAG, "commitText(" + text + ", " + newCursorPosition + ")");
         replaceText(text, newCursorPosition, false);
         sendCurrentText();
         return true;
@@ -260,7 +260,7 @@ public class BaseInputConnection implements InputConnection {
      */
     @Override
     public boolean deleteSurroundingText(int beforeLength, int afterLength) {
-        if (DEBUG) Log.v(TAG, "deleteSurroundingText " + beforeLength + " / " + afterLength);
+        if (DEBUG) Log.v(TAG, "deleteSurroundingText(" + beforeLength + ", " + afterLength + ")");
         final Editable content = getEditable();
         if (content == null) return false;
 
@@ -747,13 +747,14 @@ public class BaseInputConnection implements InputConnection {
      */
     @Override
     public boolean setComposingText(CharSequence text, int newCursorPosition) {
-        if (DEBUG) Log.v(TAG, "setComposingText " + text);
+        if (DEBUG) Log.v(TAG, "setComposingText(" + text + ", " + newCursorPosition + ")");
         replaceText(text, newCursorPosition, true);
         return true;
     }
 
     @Override
     public boolean setComposingRegion(int start, int end) {
+        if (DEBUG) Log.v(TAG, "setComposingRegion(" + start + ", " + end + ")");
         final Editable content = getEditable();
         if (content != null) {
             beginBatchEdit();
@@ -797,7 +798,7 @@ public class BaseInputConnection implements InputConnection {
     /** The default implementation changes the selection position in the current editable text. */
     @Override
     public boolean setSelection(int start, int end) {
-        if (DEBUG) Log.v(TAG, "setSelection " + start + ", " + end);
+        if (DEBUG) Log.v(TAG, "setSelection(" + start + ", " + end + ")");
         final Editable content = getEditable();
         if (content == null) return false;
         int len = content.length();
@@ -950,11 +951,22 @@ public class BaseInputConnection implements InputConnection {
             setComposingSpans(sp);
         }
 
-        if (DEBUG) Log.v(TAG, "Replacing from " + a + " to " + b + " with \""
-                + text + "\", composing=" + composing
-                + ", type=" + text.getClass().getCanonicalName());
-
         if (DEBUG) {
+            Log.v(
+                    TAG,
+                    "Replacing from "
+                            + a
+                            + " to "
+                            + b
+                            + " with \""
+                            + text
+                            + "\", composing="
+                            + composing
+                            + ", newCursorPosition="
+                            + newCursorPosition
+                            + ", type="
+                            + text.getClass().getCanonicalName());
+
             LogPrinter lp = new LogPrinter(Log.VERBOSE, TAG);
             lp.println("Current text:");
             TextUtils.dumpSpans(content, lp, "  ");
@@ -962,10 +974,10 @@ public class BaseInputConnection implements InputConnection {
             TextUtils.dumpSpans(text, lp, "  ");
         }
 
-        // Position the cursor appropriately, so that after replacing the
-        // desired range of text it will be located in the correct spot.
-        // This allows us to deal with filters performing edits on the text
-        // we are providing here.
+        // Position the cursor appropriately, so that after replacing the desired range of text it
+        // will be located in the correct spot.
+        // This allows us to deal with filters performing edits on the text we are providing here.
+        int requestedNewCursorPosition = newCursorPosition;
         if (newCursorPosition > 0) {
             newCursorPosition += b - 1;
         } else {
@@ -977,6 +989,13 @@ public class BaseInputConnection implements InputConnection {
 
         content.replace(a, b, text);
 
+        // Replace (or insert) to the cursor (a==b==newCursorPosition) will position the cursor to
+        // the end of the new replaced/inserted text, we need to re-position the cursor to the start
+        // according the API definition: "if <= 0, this is relative to the start of the text".
+        if (requestedNewCursorPosition == 0 && a == b) {
+            Selection.setSelection(content, newCursorPosition);
+        }
+
         if (DEBUG) {
             LogPrinter lp = new LogPrinter(Log.VERBOSE, TAG);
             lp.println("Final text:");

core/tests/coretests/src/android/view/inputmethod/BaseInputConnectionTest.java

@@ -78,25 +78,24 @@ public class BaseInputConnectionTest {
         verifyContent("text1text2text3", 15, 15, -1, -1);
 
         // before commit: "text1text2text3|"
-        // after commit: "text1text2text3text4|"
-        // BUG(b/21476564): this behavior is inconsistent with API description.
+        // after commit: "text1text2text3|text4"
         assertThat(mBaseInputConnection.commitText("text4", 0)).isTrue();
-        verifyContent("text1text2text3text4", 20, 20, -1, -1);
+        verifyContent("text1text2text3text4", 15, 15, -1, -1);
 
-        // before commit: "text1text2text3text4|"
-        // after commit: "text1text2text3text|4text5"
+        // before commit: "text1text2text3|text4"
+        // after commit: "text1text2text|3text5text4"
         assertThat(mBaseInputConnection.commitText("text5", -1)).isTrue();
-        verifyContent("text1text2text3text4text5", 19, 19, -1, -1);
+        verifyContent("text1text2text3text5text4", 14, 14, -1, -1);
 
-        // before commit: "text1text2text3text|4text5"
-        // after commit: "text1text2text3te|xttext64text5"
+        // before commit: "text1text2text|3text5text4"
+        // after commit: "text1text2te|xttext63text5text4"
         assertThat(mBaseInputConnection.commitText("text6", -2)).isTrue();
-        verifyContent("text1text2text3texttext64text5", 17, 17, -1, -1);
+        verifyContent("text1text2texttext63text5text4", 12, 12, -1, -1);
 
-        // before commit: "text1text2text3te|xttext64text5"
-        // after commit: "|text1text2text3tetext7xttext64text5"
+        // before commit: "text1text2te|xttext63text5text4"
+        // after commit: "|text1text2tetext7xttext63text5text4"
         assertThat(mBaseInputConnection.commitText("text7", -100)).isTrue();
-        verifyContent("text1text2text3tetext7xttext64text5", 0, 0, -1, -1);
+        verifyContent("text1text2tetext7xttext63text5text4", 0, 0, -1, -1);
     }
 
     @Test
@@ -296,12 +295,11 @@ public class BaseInputConnectionTest {
         verifyContent("abcdef", 6, 6, 3, 6);
 
         // before set composing text: "abc|"
-        // after set composing text: "abcdef|"
-        //                               ---
-        // BUG(b/21476564): this behavior is inconsistent with API description.
+        // after set composing text: "abc|def"
+        //                                ---
         prepareContent("abc", 3, 3, -1, -1);
         assertThat(mBaseInputConnection.setComposingText("def", 0)).isTrue();
-        verifyContent("abcdef", 6, 6, 3, 6);
+        verifyContent("abcdef", 3, 3, 3, 6);
 
         // before set composing text: "abc|"
         // after set composing text: "ab|cdef"