如何在 Android 中使用饼状图？

本例演示如何在 Android 中使用饼状图。

步骤 1 − 在 Android Studio 中创建一个新项目，转到 File ⇒ New Project，并填写所有必填信息以为创建一个新项目。

步骤 2 − 打开 build.gradle（模块级别），并添加 library 依赖项。

apply plugin: 'com.android.application'
android {
   packagingOptions {
      exclude 'META-INF/proguard/androidx-annotations.pro'
   }
   packagingOptions {
      exclude 'META-INF/DEPENDENCIES'
      exclude 'META-INF/LICENSE'
      exclude 'META-INF/LICENSE.txt'
      exclude 'META-INF/license.txt'
      exclude 'META-INF/NOTICE'
      exclude 'META-INF/NOTICE.txt'
      exclude 'META-INF/notice.txt'
      exclude 'META-INF/ASL2.0'
   }
   compileSdkVersion 28
   defaultConfig {
      applicationId "com.example.andy.myapplication"
      minSdkVersion 15
      targetSdkVersion 28
      versionCode 1
      versionName "1.0"
      testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
   }
   buildTypes {
      release {
         minifyEnabled false
         proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
      }
   }
}
dependencies {
   implementation fileTree(dir: 'libs', include: ['*.jar'])
   implementation 'com.android.support:appcompat-v7:28.0.0'
   implementation 'com.android.support.constraint:constraint-layout:1.1.3'
   implementation 'com.github.PhilJay:MPAndroidChart:v3.1.0-alpha'
   testImplementation 'junit:junit:4.12'
   androidTestImplementation 'com.android.support.test:runner:1.0.2'
   androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

步骤 3 − 打开 build.gradle（应用级别），并添加 library 依赖项。

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
   repositories {
      google()
      jcenter()
   }
   dependencies {
      classpath 'com.android.tools.build:gradle:3.2.1'
      // NOTE: Do not place your application dependencies here; they belong
      // in the individual module build.gradle files
   }
}
allprojects {
   repositories {
      google()
      jcenter()
      maven { url 'https://jitpack.io' }
   }
}
task clean(type: Delete) {
   delete rootProject.buildDir
}

步骤 4 − 将以下代码添加到 res/layout/activity_main.xml。

<?xml version = "1.0" encoding = "utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android = "http://schemas.android.com/apk/res/android"
   xmlns:app = "http://schemas.android.com/apk/res-auto"
   xmlns:tools = "http://schemas.android.com/tools"
   android:layout_width = "match_parent"
   android:layout_height = "match_parent"
   tools:context = ".MainActivity">
   <com.github.mikephil.charting.charts.PieChart
      android:id = "@+id/pieChart"
      android:layout_width = "fill_parent"
      android:layout_height = "fill_parent" />
</android.support.constraint.ConstraintLayout>

在上面的代码中，我们采用的 pieChart 视图来显示饼状图

步骤 4 − 将以下代码添加到 src/MainActivity.java

package com.example.andy.myapplication;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import com.github.mikephil.charting.charts.PieChart;
import com.github.mikephil.charting.data.PieData;
import com.github.mikephil.charting.data.PieDataSet;
import com.github.mikephil.charting.data.PieEntry;
import com.github.mikephil.charting.utils.ColorTemplate;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
   PieChart pieChart;
   PieData pieData;
   PieDataSet pieDataSet;
   ArrayList pieEntries;
   ArrayList PieEntryLabels;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      pieChart = findViewById(R.id.pieChart);
      getEntries();
      pieDataSet = new PieDataSet(pieEntries, "");
      pieData = new PieData(pieDataSet);
      pieChart.setData(pieData);
      pieDataSet.setColors(ColorTemplate.JOYFUL_COLORS);
      pieDataSet.setSliceSpace(2f);
      pieDataSet.setValueTextColor(Color.WHITE);
      pieDataSet.setValueTextSize(10f);
      pieDataSet.setSliceSpace(5f);
   }
   private void getEntries() {
      pieEntries = new ArrayList<>();
      pieEntries.add(new PieEntry(2f, 0));
      pieEntries.add(new PieEntry(4f, 1));
      pieEntries.add(new PieEntry(6f, 2));
      pieEntries.add(new PieEntry(8f, 3));
      pieEntries.add(new PieEntry(7f, 4));
      pieEntries.add(new PieEntry(3f, 5));
   }
}

让我们尝试运行你的应用程序。我假设你已经将你的实际 Android 移动设备连接到你的电脑上。要从 Android Studio 运行该应用程序，请打开你的一个项目活动文件，然后点击工具栏上的 Run 图标。选择你的移动设备作为一个选项，然后查看将显示你的默认屏幕的你的移动设备–