点按时显示值[MPAndroidChart]

Question

我一直在寻找一种方法来使MPAndroidChart只在点击时显示数据点的值(标签).但似乎即使在文档中我也无法在线找到它.

我使用的line chart和我想要的只是在点击时只显示某个点的标签.

Answer 1

1- 在图表中启用触摸

chart.setTouchEnabled(true);

2 - 创建MarkerView

public class CustomMarkerView extends MarkerView {

    private TextView tvContent;
    public CustomMarkerView (Context context, int layoutResource) {
        super(context, layoutResource);
        // this markerview only displays a textview
        tvContent = (TextView) findViewById(R.id.tvContent);
    }

    // callbacks everytime the MarkerView is redrawn, can be used to update the
    // content (user-interface)
    @Override
    public void refreshContent(Entry e, Highlight highlight) {
        tvContent.setText("" + e.getVal()); // set the entry-value as the display text
    }

    @Override
    public int getXOffset() {
        // this will center the marker-view horizontally
        return -(getWidth() / 2);
    }

    @Override
    public int getYOffset() {
        // this will cause the marker-view to be above the selected value
        return -getHeight();
    }
}

3 - 创建tvContent视图

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="40dp"
    android:background="@drawable/markerImage" >

    <TextView
        android:id="@+id/tvContent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="7dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:text=""
        android:textSize="12dp"
        android:textColor="@android:color/white"
        android:ellipsize="end"
        android:singleLine="true"
        android:textAppearance="?android:attr/textAppearanceSmall" />

</RelativeLayout>

4.在图表中设置视图标记

CustomMarkerView mv = new CustomMarkerView (Context, R.layout.custom_marker_view_layout);
chart.setMarkerView(mv);

https://github.com/PhilJay/MPAndroidChart/wiki/MarkerView

Answer 2

使用IMarker界面（从3.0.0版开始不推荐使用MarkerView）

1.创建一个实现IMarker接口的新类

public class YourMarkerView extends MarkerView {

private TextView tvContent;

public MyMarkerView(Context context, int layoutResource) {
    super(context, layoutResource);

    // find your layout components
    tvContent = (TextView) findViewById(R.id.tvContent);
}

// callbacks everytime the MarkerView is redrawn, can be used to update the
// content (user-interface)
@Override
public void refreshContent(Entry e, Highlight highlight) {

    tvContent.setText("" + e.getY());

    // this will perform necessary layouting
    super.refreshContent(e, highlight);
}

private MPPointF mOffset; 

@Override
public MPPointF getOffset() {

    if(mOffset == null) {
       // center the marker horizontally and vertically
       mOffset = new MPPointF(-(getWidth() / 2), -getHeight());
    }

    return mOffset;
}}

2.将标记设置为图表

IMarker marker = new YourMarkerView();
chart.setMarker(marker);

参考：https : //github.com/PhilJay/MPAndroidChart/wiki/IMarker-Interface