Question

要加载我的页面，我必须按特定顺序制作几个AJAX POSTS，我通过使用.done（）函数实现了这一点：

import android.graphics.Color;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;

public class MaterialColorPalette {

  public static final int RED_500 = 0xFFF44336;
  public static final int PINK_500 = 0xFFE91E63;
  public static final int PURPLE_500 = 0xFF9C27B0;
  public static final int DEEP_PURPLE_500 = 0xFF673AB7;
  public static final int INDIGO_500 = 0xFF3F51B5;
  public static final int BLUE_500 = 0xFF2196F3;
  public static final int LIGHT_BLUE_500 = 0xFF03A9F4;
  public static final int CYAN_500 = 0xFF00BCD4;
  public static final int TEAL_500 = 0xFF009688;
  public static final int GREEN_500 = 0xFF4CAF50;
  public static final int LIGHT_GREEN_500 = 0xFF8BC34A;
  public static final int LIME_500 = 0xFFCDDC39;
  public static final int YELLOW_500 = 0xFFFFEB3B;
  public static final int AMBER_500 = 0xFFFFC107;
  public static final int ORANGE_500 = 0xFFFF9800;
  public static final int DEEP_ORANGE_500 = 0xFFFF5722;
  public static final int BROWN_500 = 0xFF795548;
  public static final int GREY_500 = 0xFF9E9E9E;
  public static final int BLUE_GREY_500 = 0xFF607D8B;

  private static final List<MaterialColorPalette> MATERIAL_PALETTES;

  private static final Random RANDOM = new Random();

  static {
    MATERIAL_PALETTES = new ArrayList<>();
    MATERIAL_PALETTES.add(new MaterialColorPalette(RED_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(PINK_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(PURPLE_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(DEEP_PURPLE_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(INDIGO_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(BLUE_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(LIGHT_BLUE_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(CYAN_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(TEAL_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(GREEN_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(LIGHT_GREEN_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(LIME_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(YELLOW_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(AMBER_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(ORANGE_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(DEEP_ORANGE_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(BROWN_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(GREY_500));
    MATERIAL_PALETTES.add(new MaterialColorPalette(BLUE_GREY_500));
  }

  public static int getRandomColor(String key) {
    return MATERIAL_PALETTES.get(RANDOM.nextInt(MATERIAL_PALETTES.size())).getColor(key);
  }

  /**
   * Lighten or darken a color
   *
   * @param color
   *     color value
   * @param percent
   *     -1.0 to 1.0
   * @return new shaded color
   * @see #shadeColor(String, double)
   */
  public static int shadeColor(int color, double percent) {
    return shadeColor(String.format("#%06X", (0xFFFFFF & color)), percent); // ignores alpha channel
  }

  /**
   * Lighten or darken a color
   *
   * @param color
   *     7 character string representing the color.
   * @param percent
   *     -1.0 to 1.0
   * @return new shaded color
   * @see #shadeColor(int, double)
   */
  public static int shadeColor(String color, double percent) {
    // based off http://stackoverflow.com/a/13542669/1048340
    long f = Long.parseLong(color.substring(1), 16);
    double t = percent < 0 ? 0 : 255;
    double p = percent < 0 ? percent * -1 : percent;
    long R = f >> 16;
    long G = f >> 8 & 0x00FF;
    long B = f & 0x0000FF;
    int red = (int) (Math.round((t - R) * p) + R);
    int green = (int) (Math.round((t - G) * p) + G);
    int blue = (int) (Math.round((t - B) * p) + B);
    return Color.rgb(red, green, blue);
  }

  private final HashMap<String, Integer> palette = new HashMap<>();

  /**
   * @param primary
   *     the 500 color
   */
  public MaterialColorPalette(int primary) {
    palette.put("50", shadeColor(primary, 0.9));
    palette.put("100", shadeColor(primary, 0.7));
    palette.put("200", shadeColor(primary, 0.5));
    palette.put("300", shadeColor(primary, 0.333));
    palette.put("400", shadeColor(primary, 0.166));
    palette.put("500", primary);
    palette.put("600", shadeColor(primary, -0.125));
    palette.put("700", shadeColor(primary, -0.25));
    palette.put("800", shadeColor(primary, -0.375));
    palette.put("900", shadeColor(primary, -0.5));
    palette.put("A100", shadeColor(primary, 0.7));
    palette.put("A200", shadeColor(primary, 0.5));
    palette.put("A400", shadeColor(primary, 0.166));
    palette.put("A700", shadeColor(primary, -0.25));
  }

  public int getColor(String key) {
    return palette.get(key);
  }

  public void putColor(String key, int color) {
    palette.put(key, color);
  }

}

现在我正在尝试实现错误处理，以便当检测到错误（由我或HTTP错误代码）加载停止并显示错误消息时，我无法弄清楚如何执行此操作：< / p>

$(document).ready(function(){
    // Load Recipients & documents
    $("#page").hide();
    $("#loading").show();

    // Specify the loading order
    load_recipients().done(function(){
        load_documents().done(function() {
            $.when( initialize() ).then(function() {
                var deferreds = [];
                page_list.forEach(function(page_id, index) {
                    deferreds.push(load_fields(page_id));
                });

                $.when.apply(null, deferreds).done(function() {
                    $("#page").show();
                    $("#loading").hide();
                });
            });
        });
    });
});

到目前为止，我已尝试过e.preventDefault（）,. stop（）和stopPropogation（），但它们都没有阻止下一次发生AJAX POST。有没有人对我如何处理这个有任何建议？

Answer 1

您可以创建自己的承诺，以便自己解决或拒绝。

function load_recipients() {
    var promise = $.Deferred().promise();
    $.ajax({
        url: base_url + "recipients/get/",
        type: "POST",
        data: { 
            packets_id : packets_id
        },
        success: function(response_data) {
            recipient_list = JSON.parse(response_data);
            if(recipient_list.hasOwnProperty('error')) {
                 promise.reject();
            } else {
                promise.resolve();
            }
        },
        error: function(jqXHR){
            promise.reject();
        }
    });
    return promise;
}

至于处理拒绝，我相信$ .when（）。然后处理这个。

https://api.jquery.com/deferred.then/

deferred.then( doneFilter [, failFilter ] [, progressFilter ] )

doneFilter类型：Function（）解析Deferred时调用的函数。

failFilter类型：Function（）拒绝延迟时调用的可选函数。

Answer 2

我不确定这是否是实现我想要做的最好或最优雅的方式，但它确实有效。我将成功检查移到了完成功能。

$(document).ready(function(){
    // Load Recipients & documents
    $("#page").hide();
    $("#loading").show();

    // Specify the loading order
    load_recipients().done(function(data){

        recipient_list = JSON.parse(data);
        if(recipient_list.hasOwnProperty('error')) {
            $("#alert-section .alert-danger").html("Please verify a recipient exists for this packet <a href='#'>Go Back</a>");
            $("#alert-section .alert-danger").removeClass("hidden");
            return false;   // Prevents next AJAX POST
        } else {
            console.log("It's all good in the hood");
        }

        load_documents().done(function() {
            $.when( initialize() ).then(function() {
                var deferreds = [];
                page_list.forEach(function(page_id, index) {
                    deferreds.push(load_fields(page_id));
                });

                $.when.apply(null, deferreds).done(function() {
                    $("#page").show();
                    $("#loading").hide();
                });
            });
        });
    });
});

function load_recipients() {
    return $.ajax({
        url: base_url + "recipients/get/",
        type: "POST",
        data: { 
            packets_id : packets_id
        },
        error: function(jqXHR){
            // When this error is hit, all subsequent AJAX POSTs are stopped automatically
            $("#alert-section .alert-danger").html("Please verify a recipient exists for this packet <a href='#'>Go Back</a>");
            $("#alert-section .alert-danger").removeClass("hidden");
        }
    });
}

停止AJAX通话

2 个答案: