Android中使用Jetpack Compose的ProressBar

ProressBar是Android中的重要UI组件，用于指示任何过程的进度，例如显示任何下载过程，显示为占位符屏幕等等。在本文中，我们将介绍使用Jetpack Compose在Android中实现ProressBar的方法。

Attributes	Uses
modifier	to add padding to our progress Bar.
color	to add color to our progress Bar.
strokeWidth	this attribute is used to give the width of the circular line of the progress Bar.
progress	to indicate the progress of your circular progress Bar.

分步实施

步骤1：创建一个新项目

要在Android Studio Canary版本中创建新项目，请参阅如何使用Jetpack Compose在Android Studio Canary版本中创建新项目。

步骤2：使用MainActivity.kt文件

导航到应用程序> Java >您的应用程序的程序包名称，然后打开MainActivity.kt文件。在该文件内，添加以下代码。在代码内部添加了注释，以更详细地了解代码。

Kotlin

import android.graphics.drawable.shapes.Shape
import android.media.Image
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.compose.foundation.*
import androidx.compose.foundation.Text
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material.*
import androidx.compose.material.Icon
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.AccountCircle
import androidx.compose.material.icons.filled.Info
import androidx.compose.material.icons.filled.Menu
import androidx.compose.material.icons.filled.Phone
import androidx.compose.runtime.*
import androidx.compose.runtime.savedinstancestate.savedInstanceState
import androidx.compose.ui.Alignment
import androidx.compose.ui.layout.ContentScale
import androidx.compose.ui.platform.setContent
import androidx.compose.ui.res.imageResource
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.example.gfgapp.ui.GFGAppTheme
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.SolidColor
import androidx.compose.ui.platform.ContextAmbient
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.res.colorResource
import androidx.compose.ui.semantics.SemanticsProperties.ToggleableState
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.text.input.*
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.TextUnit
  
class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Column {
                // in below line we are calling 
                  // a progress bar  method.
                SimpleCircularProgressComponent()
            }
        }
    }
}
  
@Preview(showBackground = true)
@Composable
fun DefaultPreview() {
    GFGAppTheme {
        SimpleCircularProgressComponent();
    }
}
  
@Composable
fun SimpleCircularProgressComponent() {
    // CircularProgressIndicator is generally used
    // at the loading screen and it indicates that
    // some progress is going on so please wait.
    Column(
        // we are using column to align our
        // imageview to center of the screen.
        modifier = Modifier.fillMaxWidth().fillMaxHeight(),
  
        // below line is used for specifying
        // vertical arrangement.
        verticalArrangement = Arrangement.Center,
  
        // below line is used for specifying
        // horizontal arrangement.
        horizontalAlignment = Alignment.CenterHorizontally,
  
        ) {
        // below line is use to display 
        // a circular progress bar.
        CircularProgressIndicator(
            // below line is use to add padding
            // to our progress bar.
            modifier = Modifier.padding(16.dp),
              
            // below line is use to add color 
            // to our progress bar.
            color = colorResource(id = R.color.purple_200),
              
            // below line is use to add stroke 
            // width to our progress bar.
            strokeWidth = Dp(value = 4F)
        )
    }
}

现在运行您的应用程序，并查看该应用程序的输出。

输出：

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