diff --git a/android/app/src/main/java/io/github/kichikuou/system3/GameActivity.kt b/android/app/src/main/java/io/github/kichikuou/system3/GameActivity.kt
index 74a215a..bc3e07a 100644
--- a/android/app/src/main/java/io/github/kichikuou/system3/GameActivity.kt
+++ b/android/app/src/main/java/io/github/kichikuou/system3/GameActivity.kt
@@ -77,14 +77,15 @@ class GameActivity : SDLActivity() {
         Launcher.updateGameList()
     }
 
-    private fun textInputDialog(oldVal: String, result: Array<String?>) {
+    private fun textInputDialog(oldVal: String, maxLen: Int, result: Array<String?>) {
         val input = EditText(this)
         input.inputType = InputType.TYPE_CLASS_TEXT
         input.setText(oldVal)
         AlertDialog.Builder(this)
+                .setMessage(getString(R.string.input_dialog_message, maxLen))
                 .setView(input)
                 .setPositiveButton(R.string.ok) {_, _ ->
-                    result[0] = input.text.toString()
+                    result[0] = input.text.toString().substring(0, maxLen)
                 }
                 .setNegativeButton(R.string.cancel) {_, _ -> }
                 .setOnDismissListener {
@@ -103,9 +104,9 @@ class GameActivity : SDLActivity() {
     @Suppress("unused") fun midiStop() = midi.stop()
     @Suppress("unused") fun midiCurrentPosition() = midi.currentPosition()
 
-    @Suppress("unused") fun inputString(oldVal: String): String? {
+    @Suppress("unused") fun inputString(oldVal: String, maxLen: Int): String? {
         val result = arrayOfNulls<String?>(1)
-        runOnUiThread { textInputDialog(oldVal, result) }
+        runOnUiThread { textInputDialog(oldVal, maxLen, result) }
         // Block the calling thread.
         synchronized(result) {
             try {
diff --git a/android/app/src/main/res/values-ja/strings.xml b/android/app/src/main/res/values-ja/strings.xml
index 4c06760..afe6f4f 100644
--- a/android/app/src/main/res/values-ja/strings.xml
+++ b/android/app/src/main/res/values-ja/strings.xml
@@ -7,6 +7,7 @@
     <string name="cannot_find_adisk">System3 のファイル (*.dat) が見つかりません。</string>
     <string name="choose_a_file">ファイルを選択</string>
     <string name="error_dialog_title">エラー</string>
+    <string name="input_dialog_message">文字列を入力してください（最大%d文字）</string>
     <string name="install_dialog_title">インストール中…</string>
     <string name="install_from_zip">ZIP からインストール</string>
     <string name="install_progress">%s を展開中</string>
diff --git a/android/app/src/main/res/values/strings.xml b/android/app/src/main/res/values/strings.xml
index d4d240c..585392a 100644
--- a/android/app/src/main/res/values/strings.xml
+++ b/android/app/src/main/res/values/strings.xml
@@ -6,6 +6,7 @@
     <string name="cannot_find_adisk">Cannot find System3 game files (*.dat).</string>
     <string name="choose_a_file">Choose a file</string>
     <string name="error_dialog_title">Error</string>
+    <string name="input_dialog_message">Enter a string (up to %d characters)</string>
     <string name="install_dialog_title">Installing…</string>
     <string name="install_from_zip">Install from ZIP</string>
     <string name="install_progress">Extracting %s</string>
diff --git a/src/android/nact_android.cpp b/src/android/nact_android.cpp
index 13dd68b..4add408 100644
--- a/src/android/nact_android.cpp
+++ b/src/android/nact_android.cpp
@@ -17,8 +17,8 @@ void NACT::text_dialog()
 		WARNING("Failed to allocate a string");
 		return;
 	}
-	jmethodID mid = jni.GetMethodID("inputString", "(" STRING ")" STRING);
-	jstring jnewstr = (jstring)jni.env()->CallObjectMethod(jni.context(), mid, joldstr);
+	jmethodID mid = jni.GetMethodID("inputString", "(" STRING "I)" STRING);
+	jstring jnewstr = (jstring)jni.env()->CallObjectMethod(jni.context(), mid, joldstr, tvar_maxlen);
 	if (!jnewstr)
 		return;
 	const char* newstr_utf8 = jni.env()->GetStringUTFChars(jnewstr, NULL);