State based TF snippets

compose/snippets/src/main/java/com/example/compose/snippets/text/StateBasedText.kt

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+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.compose.snippets.text
+
+import android.text.TextUtils
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.text.BasicTextField
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.text.input.InputTransformation
+import androidx.compose.foundation.text.input.OutputTransformation
+import androidx.compose.foundation.text.input.TextFieldBuffer
+import androidx.compose.foundation.text.input.TextFieldLineLimits
+import androidx.compose.foundation.text.input.TextFieldState
+import androidx.compose.foundation.text.input.clearText
+import androidx.compose.foundation.text.input.insert
+import androidx.compose.foundation.text.input.maxLength
+import androidx.compose.foundation.text.input.rememberTextFieldState
+import androidx.compose.foundation.text.input.selectAll
+import androidx.compose.foundation.text.input.setTextAndPlaceCursorAtEnd
+import androidx.compose.foundation.text.input.then
+//noinspection UsingMaterialAndMaterial3Libraries
+import androidx.compose.material.TextField
+//noinspection UsingMaterialAndMaterial3Libraries
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import androidx.core.text.isDigitsOnly
+import androidx.lifecycle.ViewModel
+
+@Composable
+fun StateBasedTextSnippets() {
+    // [START android_compose_state_text_1]
+    BasicTextField(state = rememberTextFieldState())
+
+    TextField(state = rememberTextFieldState())
+    // [END android_compose_state_text_1]
+}
+
+@Composable
+fun StyleTextField() {
+    // [START android_compose_state_text_2]
+    TextField(
+        state = rememberTextFieldState(),
+        lineLimits = TextFieldLineLimits.MultiLine(maxHeightInLines = 2),
+        placeholder = { Text("") },
+        textStyle = TextStyle(color = Color.Blue, fontWeight = FontWeight.Bold),
+        modifier = Modifier.padding(20.dp)
+    )
+    // [END android_compose_state_text_2]
+}
+
+@Composable
+fun ConfigureLineLimits() {
+    // [START android_compose_state_text_3]
+    TextField(
+        state = rememberTextFieldState(),
+        lineLimits = TextFieldLineLimits.SingleLine
+    )
+    // [END android_compose_state_text_3]
+
+    // [START android_compose_state_text_4]
+    TextField(
+        state = rememberTextFieldState(),
+        lineLimits = TextFieldLineLimits.MultiLine(1, 4)
+    )
+    // [END android_compose_state_text_4]
+}
+
+@Composable
+fun StyleWithBrush() {
+    // [START android_compose_state_text_5]
+    val brush = remember {
+        Brush.linearGradient(
+            colors = listOf(Color.Red, Color.Yellow, Color.Green, Color.Blue, Color.Magenta)
+        )
+    }
+    TextField(
+        state = rememberTextFieldState(), textStyle = TextStyle(brush = brush)
+    )
+    // [END android_compose_state_text_5]
+}
+
+@Composable
+fun StateHoisting() {
+    // [START android_compose_state_text_6]
+    val usernameState = rememberTextFieldState()
+    TextField(
+        state = usernameState,
+        lineLimits = TextFieldLineLimits.SingleLine,
+        placeholder = { Text("Enter Username") }
+    )
+    // [END android_compose_state_text_6]
+}
+
+@Composable
+fun TextFieldInitialState() {
+    // [START android_compose_state_text_7]
+    TextField(
+        state = rememberTextFieldState(initialText = "Username"),
+        lineLimits = TextFieldLineLimits.SingleLine,
+    )
+    // [END android_compose_state_text_7]
+}
+
+@Composable
+fun TextFieldBuffer() {
+    // [START android_compose_state_text_8]
+    val phoneNumberState = rememberTextFieldState()
+
+    LaunchedEffect(phoneNumberState) {
+        phoneNumberState.edit { // TextFieldBuffer scope
+            append("123456789")
+        }
+    }
+
+    TextField(
+        state = phoneNumberState,
+        inputTransformation = InputTransformation { // TextFieldBuffer scope
+            if (asCharSequence().isDigitsOnly()) {
+                revertAllChanges()
+            }
+        },
+        outputTransformation = OutputTransformation {
+            if (length > 0) insert(0, "(")
+            if (length > 4) insert(4, ")")
+            if (length > 8) insert(8, "-")
+        }
+    )
+    // [END android_compose_state_text_8]
+}
+
+@Preview
+@Composable
+fun EditTextFieldState() {
+    // [START android_compose_state_text_9]
+    val usernameState = rememberTextFieldState("I love Android")
+    // textFieldState.text : I love Android
+    // textFieldState.selection: TextRange(14, 14)
+    usernameState.edit { insert(14, "!") }
+    // textFieldState.text : I love Android!
+    // textFieldState.selection: TextRange(15, 15)
+    usernameState.edit { replace(7, 14, "Compose") }
+    // textFieldState.text : I love Compose!
+    // textFieldState.selection: TextRange(15, 15)
+    usernameState.edit { append("!!!") }
+    // textFieldState.text : I love Compose!!!!
+    // textFieldState.selection: TextRange(18, 18)
+    usernameState.edit { selectAll() }
+    // textFieldState.text : I love Compose!!!!
+    // textFieldState.selection: TextRange(0, 18)
+    // [END android_compose_state_text_9]
+
+    // [START android_compose_state_text_10]
+    usernameState.setTextAndPlaceCursorAtEnd("I really love Android")
+    // textFieldState.text : I really love Android
+    // textFieldState.selection : TextRange(21, 21)
+    // [END android_compose_state_text_10]
+
+    // [START android_compose_state_text_11]
+    usernameState.clearText()
+    // textFieldState.text :
+    // textFieldState.selection : TextRange(0, 0)
+    // [END android_compose_state_text_11]
+}
+
+class TextFieldViewModel : ViewModel() {
+    val usernameState = TextFieldState()
+    fun validateUsername() {
+    }
+}
+val textFieldViewModel = TextFieldViewModel()
+
+@Composable
+fun TextFieldKeyboardOptions() {
+    // [START android_compose_state_text_13]
+    TextField(
+        state = textFieldViewModel.usernameState,
+        keyboardOptions = KeyboardOptions(imeAction = ImeAction.Next),
+        onKeyboardAction = { performDefaultAction ->
+            textFieldViewModel.validateUsername()
+            performDefaultAction()
+        }
+    )
+    // [END android_compose_state_text_13]
+}
+
+@Composable
+fun TextFieldInputTransformation() {
+    // [START android_compose_state_text_14]
+    TextField(
+        state = rememberTextFieldState(),
+        lineLimits = TextFieldLineLimits.SingleLine,
+        inputTransformation = InputTransformation.maxLength(10)
+    )
+    // [END android_compose_state_text_14]
+}
+
+// [START android_compose_state_text_15]
+class CustomInputTransformation : InputTransformation {
+    override fun TextFieldBuffer.transformInput() {
+    }
+}
+// [END android_compose_state_text_15]
+
+// [START android_compose_state_text_16]
+class DigitOnlyInputTransformation : InputTransformation {
+    override fun TextFieldBuffer.transformInput() {
+        if (!TextUtils.isDigitsOnly(asCharSequence())) {
+            revertAllChanges()
+        }
+    }
+}
+// [END android_compose_state_text_16]
+
+@Composable
+fun ChainInputTransformation() {
+    // [START android_compose_state_text_17]
+    TextField(
+        state = rememberTextFieldState(),
+        inputTransformation = InputTransformation.maxLength(6)
+            .then(CustomInputTransformation()),
+    )
+    // [END android_compose_state_text_17]
+}
+
+// [START android_compose_state_text_18]
+class CustomOutputTransformation : OutputTransformation {
+    override fun TextFieldBuffer.transformOutput() {
+    }
+}
+// [END android_compose_state_text_18]
+
+// [START android_compose_state_text_19]
+class PhoneNumberOutputTransformation : OutputTransformation {
+    override fun TextFieldBuffer.transformOutput() {
+        if (length > 0) insert(0, "(")
+        if (length > 4) insert(4, ")")
+        if (length > 8) insert(8, "-")
+    }
+}
+// [END android_compose_state_text_19]
+
+@Composable
+fun TextFieldOutputTransformation() {
+    // [START android_compose_state_text_20]
+    TextField(
+        state = rememberTextFieldState(),
+        outputTransformation = PhoneNumberOutputTransformation()
+    )
+    // [END android_compose_state_text_20]
+}