如何在Android中使用折線圖？

此示例演示如何在Android中使用折線圖。

步驟1 - 在Android Studio中建立一個新專案，轉到檔案 ⇒ 新建專案，並填寫所有必需的詳細資訊以建立新專案。

步驟2 - 開啟build.gradle（模組級）並新增庫依賴項。

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'
}

步驟3 - 開啟build.gradle（應用程式級）並新增庫依賴項。

// 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
}

步驟4 - 將以下程式碼新增到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.LineChart
      android:id = "@+id/lineChart"
      android:layout_width = "fill_parent"
      android:layout_height = "fill_parent" />
</android.support.constraint.ConstraintLayout>

在上面的程式碼中，我們使用了折線圖檢視來顯示折線圖。

步驟5 - 將以下程式碼新增到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.LineChart;
import com.github.mikephil.charting.data.Entry;
import com.github.mikephil.charting.data.LineData;
import com.github.mikephil.charting.data.LineDataSet;
import com.github.mikephil.charting.utils.ColorTemplate;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
   LineChart lineChart;
   LineData lineData;
   LineDataSet lineDataSet;
   ArrayList lineEntries;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      lineChart = findViewById(R.id.lineChart);
      getEntries();
      lineDataSet = new LineDataSet(lineEntries, "");
      lineData = new LineData(lineDataSet);
      lineChart.setData(lineData);
      lineDataSet.setColors(ColorTemplate.JOYFUL_COLORS);
      lineDataSet.setValueTextColor(Color.BLACK);
      lineDataSet.setValueTextSize(18f);
   }
   private void getEntries() {
      lineEntries = new ArrayList<>();
      lineEntries.add(new Entry(2f, 0));
      lineEntries.add(new Entry(4f, 1));
      lineEntries.add(new Entry(6f, 1));
      lineEntries.add(new Entry(8f, 3));
      lineEntries.add(new Entry(7f, 4));
      lineEntries.add(new Entry(3f, 3));
   }
}

讓我們嘗試執行您的應用程式。我假設您已將實際的Android移動裝置連線到您的計算機。要從Android Studio執行應用程式，請開啟專案中的一個活動檔案，然後單擊執行工具欄中的圖示。選擇您的移動裝置作為選項，然後檢查您的移動裝置，它將顯示您的預設螢幕 -