Add line graph to statistics screen

1 files changed, 138 insertions, 0 deletions

diff --git a/app/src/main/java/de/danoeh/antennapod/view/LineChartView.java b/app/src/main/java/de/danoeh/antennapod/view/LineChartView.java
new file mode 100644
index 000000000..0eb225e8e
--- /dev/null
+++ b/app/src/main/java/de/danoeh/antennapod/view/LineChartView.java
@@ -0,0 +1,138 @@
+package de.danoeh.antennapod.view;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.ColorFilter;
+import android.graphics.DashPathEffect;
+import android.graphics.LinearGradient;
+import android.graphics.Paint;
+import android.graphics.Path;
+import android.graphics.PixelFormat;
+import android.graphics.Shader;
+import android.graphics.drawable.Drawable;
+import android.util.AttributeSet;
+import androidx.annotation.NonNull;
+import androidx.appcompat.widget.AppCompatImageView;
+import androidx.appcompat.widget.ThemeUtils;
+import de.danoeh.antennapod.R;
+import io.reactivex.annotations.Nullable;
+
+public class LineChartView extends AppCompatImageView {
+    private LineChartDrawable drawable;
+
+    public LineChartView(Context context) {
+        super(context);
+        setup();
+    }
+
+    public LineChartView(Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+        setup();
+    }
+
+    public LineChartView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        setup();
+    }
+
+    @SuppressLint("ClickableViewAccessibility")
+    private void setup() {
+        drawable = new LineChartDrawable();
+        setImageDrawable(drawable);
+    }
+
+    /**
+     * Set of data values to display.
+     */
+    public void setData(LineChartData data) {
+        drawable.data = data;
+    }
+
+    public static class LineChartData {
+        private final long valueMax;
+        private final long[] values;
+        private final long[] verticalLines;
+
+        public LineChartData(long[] values, long[] verticalLines) {
+            this.values = values;
+            long valueMax = 0;
+            for (long datum : values) {
+                valueMax = Math.max(datum, valueMax);
+            }
+            this.valueMax = valueMax;
+            this.verticalLines = verticalLines;
+        }
+
+        public float getHeight(int item) {
+            return (float) values[item] / valueMax;
+        }
+    }
+
+    private class LineChartDrawable extends Drawable {
+        private LineChartData data;
+        private final Paint paintLine;
+        private final Paint paintBackground;
+        private final Paint paintVerticalLines;
+
+        private LineChartDrawable() {
+            paintLine = new Paint();
+            paintLine.setFlags(Paint.ANTI_ALIAS_FLAG);
+            paintLine.setStyle(Paint.Style.STROKE);
+            paintLine.setStrokeJoin(Paint.Join.ROUND);
+            paintLine.setStrokeCap(Paint.Cap.ROUND);
+            paintLine.setColor(ThemeUtils.getThemeAttrColor(getContext(), R.attr.colorAccent));
+            paintBackground = new Paint();
+            paintBackground.setStyle(Paint.Style.FILL);
+            paintVerticalLines = new Paint();
+            paintVerticalLines.setStyle(Paint.Style.STROKE);
+            paintVerticalLines.setPathEffect(new DashPathEffect(new float[] {10f, 10f}, 0f));
+            paintVerticalLines.setColor(0x66777777);
+        }
+
+        @Override
+        public void draw(@NonNull Canvas canvas) {
+            float width = getBounds().width();
+            float height = getBounds().height();
+            float usableHeight = height * 0.9f;
+            float stepSize = width / (data.values.length + 1);
+
+            paintVerticalLines.setStrokeWidth(height * 0.005f);
+            for (long line : data.verticalLines) {
+                canvas.drawLine((line + 1) * stepSize, 0, (line + 1) * stepSize, height, paintVerticalLines);
+            }
+
+            paintLine.setStrokeWidth(height * 0.015f);
+            Path path = new Path();
+            for (int i = 0; i < data.values.length; i++) {
+                if (i == 0) {
+                    path.moveTo((i + 1) * stepSize, (1 - data.getHeight(i)) * usableHeight + height * 0.05f);
+                } else {
+                    path.lineTo((i + 1) * stepSize, (1 - data.getHeight(i)) * usableHeight + height * 0.05f);
+                }
+            }
+            canvas.drawPath(path, paintLine);
+
+            path.lineTo(data.values.length * stepSize, height);
+            path.lineTo(stepSize, height);
+            paintBackground.setShader(new LinearGradient(0, 0, 0, height,
+                    (ThemeUtils.getThemeAttrColor(getContext(), R.attr.colorAccent) & 0xffffff) + 0x66000000,
+                    Color.TRANSPARENT, Shader.TileMode.CLAMP));
+            canvas.drawPath(path, paintBackground);
+        }
+
+        @Override
+        public int getOpacity() {
+            return PixelFormat.TRANSLUCENT;
+        }
+
+        @Override
+        public void setAlpha(int alpha) {
+        }
+
+        @Override
+        public void setColorFilter(ColorFilter cf) {
+        }
+    }
+}