Gantt feature

GANTT_CHART.md

@@ -0,0 +1,145 @@
+# Gantt Chart Feature
+
+A native Gantt chart implementation for MPAndroidChart that visualizes tasks as horizontal bars positioned by time intervals.
+
+## Features
+
+- **Time-based positioning** - Tasks positioned by start time and duration
+- **Responsive layout** - Automatically scales to fit any number of tasks
+- **Customizable colors** - Each task can have its own color
+- **Grid lines** - Time scale visualization with grid lines and labels
+- **Clean design** - Professional appearance with task labels and borders
+
+## Usage
+
+### 1. Add to your layout XML
+
+```xml
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <com.github.mikephil.charting.charts.GanttChart
+        android:id="@+id/ganttChart"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+
+</LinearLayout>
+```
+
+### 2. Create your Activity
+
+```java
+package com.example.myapp;
+
+import android.graphics.Color;
+import android.os.Bundle;
+import androidx.appcompat.app.AppCompatActivity;
+import com.github.mikephil.charting.charts.GanttChart;
+import com.github.mikephil.charting.data.GanttChartData;
+import com.github.mikephil.charting.data.GanttTask;
+
+public class GanttChartActivity extends AppCompatActivity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_gantt_chart);
+
+        GanttChart chart = findViewById(R.id.ganttChart);
+
+        // Create Gantt chart data
+        GanttChartData ganttData = new GanttChartData();
+
+        // Add tasks (name, startTime, duration, color)
+        ganttData.addTask(new GanttTask("Design", 0, 30, Color.rgb(255, 107, 107)));
+        ganttData.addTask(new GanttTask("Development", 20, 40, Color.rgb(66, 165, 245)));
+        ganttData.addTask(new GanttTask("Testing", 50, 20, Color.rgb(76, 175, 80)));
+        ganttData.addTask(new GanttTask("Deployment", 65, 15, Color.rgb(255, 193, 7)));
+
+        // Set data and render
+        chart.setData(ganttData);
+    }
+}
+```
+
+## API Reference
+
+### GanttTask
+
+Represents a single task in the Gantt chart.
+
+```java
+GanttTask task = new GanttTask(
+    "Task Name",      // String: display name
+    0,                // float: start time
+    50,               // float: duration
+    Color.BLUE        // int: task color
+);
+```
+
+**Methods:**
+- `getName()` - Get task name
+- `getStartTime()` - Get start time
+- `getDuration()` - Get task duration
+- `getEndTime()` - Get end time (startTime + duration)
+- `getColor()` - Get task color
+
+### GanttChartData
+
+Container for managing tasks.
+
+```java
+GanttChartData data = new GanttChartData();
+data.addTask(task1);
+data.addTask(task2);
+data.clearTasks();
+```
+
+**Methods:**
+- `addTask(GanttTask)` - Add a single task
+- `addTasks(List<GanttTask>)` - Add multiple tasks
+- `getTasks()` - Get all tasks
+- `getTaskCount()` - Get number of tasks
+- `getMinTime()` - Get earliest start time
+- `getMaxTime()` - Get latest end time
+- `clearTasks()` - Remove all tasks
+
+### GanttChart
+
+Custom View that renders the Gantt chart.
+
+```java
+GanttChart chart = findViewById(R.id.ganttChart);
+chart.setData(ganttData);
+```
+
+**Methods:**
+- `setData(GanttChartData)` - Set chart data and trigger redraw
+
+## Example Use Cases
+
+- **Project Management** - Visualize project timeline and tasks
+- **Resource Allocation** - Show resource usage over time
+- **Production Scheduling** - Display manufacturing timeline
+- **Event Planning** - Timeline visualization for events
+
+## Tips
+
+- Use consistent time units (hours, days, weeks) across all tasks
+- Ensure start times and durations use the same scale
+- Keep task names reasonably short for better display
+- Use contrasting colors for task visibility
+
+## Customization
+
+The chart automatically scales to fit your screen size and number of tasks. All styling parameters are calculated dynamically based on:
+- Available screen space
+- Number of tasks
+- Time range of tasks
+
+For visual customization, modify the `GanttChart` class directly:
+- Adjust padding in `calculateDimensions()`
+- Change grid line color/style in `drawGrid()`
+- Modify task bar appearance in `drawTasks()`

MPChartExample/build.gradle

@@ -17,6 +17,10 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
+
+    lintOptions {
+        abortOnError false
+    }
 }
 
 dependencies {

MPChartExample/src/main/AndroidManifest.xml

@@ -12,46 +12,48 @@
         android:theme="@style/AppTheme">
         <activity
             android:name="com.xxmassdeveloper.mpchartexample.notimportant.MainActivity"
-            android:label="@string/app_name" >
+            android:label="@string/app_name"
+            android:exported="true" >
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <action android:name="android.intent.action.VIEW" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-        <activity android:name="LineChartActivity1" />
-        <activity android:name="LineChartActivity2" />
-        <activity android:name="LineChartTime" />
-        <activity android:name="BarChartActivity" />
-		<activity android:name="HorizontalBarChartActivity" />
-        <activity android:name="HorizontalBarNegativeChartActivity" />
-        <activity android:name="PieChartActivity" />
-        <activity android:name="PiePolylineChartActivity" />
-        <activity android:name="MultiLineChartActivity" />
-        <activity android:name="BarChartActivityMultiDataset" />
-        <activity android:name="DrawChartActivity" />
-        <activity android:name="ScatterChartActivity" />
-        <activity android:name="BubbleChartActivity" />
-        <activity android:name=".fragments.SimpleChartDemo" />
-        <activity android:name="ListViewBarChartActivity" />
-        <activity android:name="ListViewMultiChartActivity" />
-        <activity android:name="StackedBarActivity" />
-        <activity android:name="AnotherBarActivity" />
-        <activity android:name="InvertedLineChartActivity" />
-        <activity android:name="CandleStickChartActivity" />
-        <activity android:name="CubicLineChartActivity" />
-        <activity android:name="RadarChartActivity" />
-        <activity android:name="LineChartActivityColored" />
-        <activity android:name="DynamicalAddingActivity" />
-        <activity android:name="RealtimeLineChartActivity" />
-        <activity android:name="CombinedChartActivity" />
-        <activity android:name="PerformanceLineChart" />
-        <activity android:name="BarChartActivitySinus" />
-        <activity android:name="ScrollViewActivity" />
-        <activity android:name="StackedBarActivityNegative" />
-        <activity android:name="BarChartPositiveNegative" />
-        <activity android:name="FilledLineActivity" />
-        <activity android:name="HalfPieChartActivity" />
+        <activity android:name="LineChartActivity1" android:exported="false" />
+        <activity android:name="LineChartActivity2" android:exported="false" />
+        <activity android:name="LineChartTime" android:exported="false" />
+        <activity android:name="BarChartActivity" android:exported="false" />
+		<activity android:name="HorizontalBarChartActivity" android:exported="false" />
+        <activity android:name="HorizontalBarNegativeChartActivity" android:exported="false" />
+        <activity android:name="PieChartActivity" android:exported="false" />
+        <activity android:name="PiePolylineChartActivity" android:exported="false" />
+        <activity android:name="MultiLineChartActivity" android:exported="false" />
+        <activity android:name="BarChartActivityMultiDataset" android:exported="false" />
+        <activity android:name="DrawChartActivity" android:exported="false" />
+        <activity android:name="ScatterChartActivity" android:exported="false" />
+        <activity android:name="BubbleChartActivity" android:exported="false" />
+        <activity android:name=".fragments.SimpleChartDemo" android:exported="false" />
+        <activity android:name="ListViewBarChartActivity" android:exported="false" />
+        <activity android:name="ListViewMultiChartActivity" android:exported="false" />
+        <activity android:name="StackedBarActivity" android:exported="false" />
+        <activity android:name="AnotherBarActivity" android:exported="false" />
+        <activity android:name="InvertedLineChartActivity" android:exported="false" />
+        <activity android:name="CandleStickChartActivity" android:exported="false" />
+        <activity android:name="CubicLineChartActivity" android:exported="false" />
+        <activity android:name="RadarChartActivity" android:exported="false" />
+        <activity android:name="LineChartActivityColored" android:exported="false" />
+        <activity android:name="DynamicalAddingActivity" android:exported="false" />
+        <activity android:name="RealtimeLineChartActivity" android:exported="false" />
+        <activity android:name="CombinedChartActivity" android:exported="false" />
+        <activity android:name="PerformanceLineChart" android:exported="false" />
+        <activity android:name="BarChartActivitySinus" android:exported="false" />
+        <activity android:name="ScrollViewActivity" android:exported="false" />
+        <activity android:name="StackedBarActivityNegative" android:exported="false" />
+        <activity android:name="BarChartPositiveNegative" android:exported="false" />
+        <activity android:name="FilledLineActivity" android:exported="false" />
+        <activity android:name="HalfPieChartActivity" android:exported="false" />
+        <activity android:name="com.xxmassdeveloper.chartdemo.TimeIntervalChartActivity" android:exported="false" />
     </application>
 
 </manifest>

MPChartExample/src/main/java/com/xxmassdeveloper/chartdemo/TimeIntervalChartActivity.java

@@ -0,0 +1,39 @@
+package com.xxmassdeveloper.chartdemo;
+
+import android.graphics.Color;
+import android.os.Bundle;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import com.github.mikephil.charting.charts.GanttChart;
+import com.github.mikephil.charting.data.GanttChartData;
+import com.github.mikephil.charting.data.GanttTask;
+import com.xxmassdeveloper.mpchartexample.R;
+
+/**
+ * Demo activity showing Gantt-style timeline visualization.
+ * Each horizontal bar represents a task with start time and duration.
+ */
+public class TimeIntervalChartActivity extends AppCompatActivity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_time_interval_chart);
+
+        GanttChart chart = findViewById(R.id.chart);
+
+        // Create Gantt chart data
+        GanttChartData ganttData = new GanttChartData();
+
+        // Add sample project tasks
+        ganttData.addTask(new GanttTask("Design", 0, 50, Color.rgb(255, 107, 107)));      // Red: 0-50
+        ganttData.addTask(new GanttTask("Development", 40, 100, Color.rgb(66, 165, 245))); // Blue: 40-140
+        ganttData.addTask(new GanttTask("Testing", 120, 40, Color.rgb(76, 175, 80)));      // Green: 120-160
+        ganttData.addTask(new GanttTask("Launch", 150, 20, Color.rgb(255, 193, 7)));       // Yellow: 150-170
+
+        // Set data and render
+        chart.setData(ganttData);
+    }
+}
+

MPChartExample/src/main/res/layout/activity_time_interval_chart.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <com.github.mikephil.charting.charts.GanttChart
+        android:id="@+id/chart"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+
+</RelativeLayout>

MPChartLib/src/main/java/com/github/mikephil/charting/buffer/HorizontalBarBuffer.java

@@ -31,7 +31,8 @@ public void feed(IBarDataSet data) {
 
                 float bottom = x - barWidthHalf;
                 float top = x + barWidthHalf;
-                float left, right;
+                float left;
+                float right;
                 if (mInverted) {
                     left = y >= 0 ? y : 0;
                     right = y <= 0 ? y : 0;
@@ -52,12 +53,12 @@ public void feed(IBarDataSet data) {
 
                 float posY = 0f;
                 float negY = -e.getNegativeSum();
-                float yStart = 0f;
 
                 // fill the stack
                 for (int k = 0; k < vals.length; k++) {
 
                     float value = vals[k];
+                    float yStart;
 
                     if (value >= 0f) {
                         y = posY;
@@ -71,7 +72,8 @@ public void feed(IBarDataSet data) {
 
                     float bottom = x - barWidthHalf;
                     float top = x + barWidthHalf;
-                    float left, right;
+                    float left;
+                    float right;
                     if (mInverted) {
                         left = y >= yStart ? y : yStart;
                         right = y <= yStart ? y : yStart;