013-RecommendLoadingUITunning.md

#013: 推荐加载页面优化

#首页

##1. 创建一个自定义的ImageView类 由于要实现加载图标动态旋转的效果，创建一个自定义的继承于ImageView的类，并实现旋转效果。

LoadingView.java:

package com.jupiter.miniximalaya.views;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.widget.ImageView;

@SuppressLint("AppCompatCustomView")
public class LoadingView extends ImageView {

    private int rotateDegree = 0;

    private boolean needRotate = false;

    public LoadingView(Context context) {
        this(context, null);
    }

    public LoadingView(Context context, AttributeSet attrs) {
        this(context, attrs, 0 );
    }

    public LoadingView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        /**
         * 第一个参数是旋转的角度
         * 第二，三个参数是旋转的X,Y坐标
         */
        canvas.rotate(rotateDegree, getWidth()/2, getHeight()/2);
        super.onDraw(canvas);
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        //绑定到Window时
        needRotate = true;
        post(new Runnable() {
            @Override
            public void run() {
                rotateDegree += 30;
                rotateDegree = rotateDegree <=360 ? rotateDegree : 0;
                invalidate();
                if(needRotate) {
                    postDelayed(this, 100);
                }
            }
        });
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        //解绑窗口时
        needRotate = false;
    }
}

##2. 重新设计加载页面的布局文件

fragment_loading_view.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.jupiter.miniximalaya.views.LoadingView
        android:id="@+id/iv_recommend_loading"
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:src="@mipmap/loading"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toTopOf="@id/tv_recommend_loading"
        app:layout_constraintVertical_chainStyle="packed"
        />

    <TextView
        android:id="@+id/tv_recommend_loading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="14dp"
        android:text="@string/recommend_loading"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/iv_recommend_loading"/>
</androidx.constraintlayout.widget.ConstraintLayout>

##2. 最终效果图