一、前言

接下来我们进行动画的总结。掌握动画能让交互更加吸引人，看起来更加炫酷，让用户加深印象，爱不释手。

二、动画示例

1、示例1（基础按钮+label的组合动画）

#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_SWITCHstatic void anim_x_cb(void * var, int32_t v)
{lv_obj_set_x(var, v);
}static void sw_event_cb(lv_event_t * e)
{lv_obj_t * sw = lv_event_get_target(e);lv_obj_t * label = lv_event_get_user_data(e);if(lv_obj_has_state(sw, LV_STATE_CHECKED)) {lv_anim_t a;lv_anim_init(&a);lv_anim_set_var(&a, label);lv_anim_set_values(&a, lv_obj_get_x(label), 100);lv_anim_set_duration(&a, 500);lv_anim_set_exec_cb(&a, anim_x_cb);lv_anim_set_path_cb(&a, lv_anim_path_overshoot);lv_anim_start(&a);}else {lv_anim_t a;lv_anim_init(&a);lv_anim_set_var(&a, label);lv_anim_set_values(&a, lv_obj_get_x(label), -lv_obj_get_width(label));lv_anim_set_duration(&a, 500);lv_anim_set_exec_cb(&a, anim_x_cb);lv_anim_set_path_cb(&a, lv_anim_path_ease_in);lv_anim_start(&a);}}/*** 在事件上启动动画*/
void lv_example_anim_1(void)
{lv_obj_t * label = lv_label_create(lv_screen_active());lv_label_set_text(label, "Hello animations!");lv_obj_set_pos(label, 100, 10);lv_obj_t * sw = lv_switch_create(lv_screen_active());lv_obj_center(sw);lv_obj_add_state(sw, LV_STATE_CHECKED);lv_obj_add_event_cb(sw, sw_event_cb, LV_EVENT_VALUE_CHANGED, label);
}#endif

展示：在事件上启动动画（创建switch按钮，当点击后将label的位置进行切换，其中switch和label在创建时都添加了lv_screen_active，最终通过将按钮的切换状态和label绑定到事件回调中，在回调中监测switch状态并切换label的位置达到整体的动画效果）。

2、示例2（回放效果动画）

#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_SWITCHstatic void anim_x_cb(void * var, int32_t v)
{lv_obj_set_x(var, v);
}static void anim_size_cb(void * var, int32_t v)
{lv_obj_set_size(var, v, v);
}/*** 创建播放动画*/
void lv_example_anim_2(void)
{lv_obj_t * obj = lv_obj_create(lv_screen_active());lv_obj_set_style_bg_color(obj, lv_palette_main(LV_PALETTE_RED), 0);lv_obj_set_style_radius(obj, LV_RADIUS_CIRCLE, 0);lv_obj_align(obj, LV_ALIGN_LEFT_MID, 10, 0);lv_anim_t a;lv_anim_init(&a);lv_anim_set_var(&a, obj);lv_anim_set_values(&a, 10, 50);lv_anim_set_duration(&a, 1000);lv_anim_set_playback_delay(&a, 100);lv_anim_set_playback_duration(&a, 300);lv_anim_set_repeat_delay(&a, 500);lv_anim_set_repeat_count(&a, LV_ANIM_REPEAT_INFINITE);lv_anim_set_path_cb(&a, lv_anim_path_ease_in_out);lv_anim_set_exec_cb(&a, anim_size_cb);lv_anim_start(&a);lv_anim_set_exec_cb(&a, anim_x_cb);lv_anim_set_values(&a, 10, 240);lv_anim_start(&a);
}#endif

展示：创建一个回放动画（创建播放动画的延迟和时间，然后进行重复，在回掉中设置大小和位置就实现了回放动画）

3、示例3（贝塞尔曲线3动画）

#include "../lv_examples.h"
#if LV_BUILD_EXAMPLES && LV_USE_SLIDER && LV_USE_CHART && LV_USE_BUTTON && LV_USE_GRID/*** 该示例展示了在动画中使用cubic-bezier3。* 贝塞尔曲线3的控制点P1、P2可以通过滑块调整。* 图表实时显示三次贝塞尔曲线。你可以点击运行按钮在cubic-bezier3的当前点查看动画。*/#define CHART_POINTS_NUM 256struct {lv_obj_t * anim_obj;lv_obj_t * chart;lv_chart_series_t * ser1;lv_obj_t * p1_slider;lv_obj_t * p1_label;lv_obj_t * p2_slider;lv_obj_t * p2_label;lv_obj_t * run_btn;uint16_t p1;uint16_t p2;lv_anim_t a;
} ginfo;static int32_t anim_path_bezier3_cb(const lv_anim_t * a);
static void refer_chart_cubic_bezier(void);
static void run_button_event_handler(lv_event_t * e);
static void slider_event_cb(lv_event_t * e);
static void page_obj_init(lv_obj_t * par);
static void anim_x_cb(void * var, int32_t v);/*** 创建动画*/
void lv_example_anim_3(void)
{static int32_t col_dsc[] = {LV_GRID_FR(1), 200, LV_GRID_FR(1), LV_GRID_TEMPLATE_LAST};static int32_t row_dsc[] = {30, 10, 10, LV_GRID_FR(1), LV_GRID_TEMPLATE_LAST};/*创建一个带有网格的容器*/lv_obj_t * cont = lv_obj_create(lv_screen_active());lv_obj_set_style_pad_all(cont, 2, LV_PART_MAIN);lv_obj_set_style_pad_column(cont, 10, LV_PART_MAIN);lv_obj_set_style_pad_row(cont, 10, LV_PART_MAIN);lv_obj_set_grid_dsc_array(cont, col_dsc, row_dsc);lv_obj_set_size(cont, 320, 240);lv_obj_center(cont);page_obj_init(cont);lv_anim_init(&ginfo.a);lv_anim_set_var(&ginfo.a, ginfo.anim_obj);int32_t end = lv_obj_get_style_width(cont, LV_PART_MAIN) -lv_obj_get_style_width(ginfo.anim_obj, LV_PART_MAIN) - 10;lv_anim_set_values(&ginfo.a, 5, end);lv_anim_set_duration(&ginfo.a, 2000);lv_anim_set_exec_cb(&ginfo.a, anim_x_cb);lv_anim_set_path_cb(&ginfo.a, anim_path_bezier3_cb);refer_chart_cubic_bezier();
}static int32_t anim_path_bezier3_cb(const lv_anim_t * a)
{uint32_t t = lv_map(a->act_time, 0, a->duration, 0, 1024);int32_t step = lv_bezier3(t, 0, ginfo.p1, ginfo.p2, 1024);int32_t new_value;new_value = step * (a->end_value - a->start_value);new_value = new_value >> 10;new_value += a->start_value;return new_value;
}static void refer_chart_cubic_bezier(void)
{for(uint16_t i = 0; i <= CHART_POINTS_NUM; i ++) {uint32_t t = i * (1024 / CHART_POINTS_NUM);int32_t step = lv_bezier3(t, 0, ginfo.p1, ginfo.p2, 1024);lv_chart_set_value_by_id2(ginfo.chart, ginfo.ser1, i, t, step);}lv_chart_refresh(ginfo.chart);
}static void anim_x_cb(void * var, int32_t v)
{lv_obj_set_style_translate_x(var, v, LV_PART_MAIN);
}static void run_button_event_handler(lv_event_t * e)
{lv_event_code_t code = lv_event_get_code(e);if(code == LV_EVENT_CLICKED) {lv_anim_start(&ginfo.a);}
}static void slider_event_cb(lv_event_t * e)
{char buf[16];lv_obj_t * label;lv_obj_t * slider = lv_event_get_target(e);if(slider == ginfo.p1_slider) {label = ginfo.p1_label;ginfo.p1 = lv_slider_get_value(slider);lv_snprintf(buf, sizeof(buf), "p1:%d", ginfo.p1);}else {label = ginfo.p2_label;ginfo.p2 = lv_slider_get_value(slider);lv_snprintf(buf, sizeof(buf), "p2:%d", ginfo.p2);}lv_label_set_text(label, buf);refer_chart_cubic_bezier();
}static void page_obj_init(lv_obj_t * par)
{ginfo.anim_obj = lv_obj_create(par);lv_obj_set_size(ginfo.anim_obj, 30, 30);lv_obj_set_align(ginfo.anim_obj, LV_ALIGN_TOP_LEFT);lv_obj_remove_flag(ginfo.anim_obj, LV_OBJ_FLAG_SCROLLABLE);lv_obj_set_style_bg_color(ginfo.anim_obj, lv_palette_main(LV_PALETTE_RED), LV_PART_MAIN);lv_obj_set_grid_cell(ginfo.anim_obj, LV_GRID_ALIGN_START, 0, 1, LV_GRID_ALIGN_START, 0, 1);ginfo.p1_label = lv_label_create(par);ginfo.p2_label = lv_label_create(par);lv_label_set_text(ginfo.p1_label, "p1:0");lv_label_set_text(ginfo.p2_label, "p2:0");lv_obj_set_grid_cell(ginfo.p1_label, LV_GRID_ALIGN_START, 0, 1, LV_GRID_ALIGN_START, 1, 1);lv_obj_set_grid_cell(ginfo.p2_label, LV_GRID_ALIGN_START, 0, 1, LV_GRID_ALIGN_START, 2, 1);ginfo.p1_slider = lv_slider_create(par);ginfo.p2_slider = lv_slider_create(par);lv_slider_set_range(ginfo.p1_slider, 0, 1024);lv_slider_set_range(ginfo.p2_slider, 0, 1024);lv_obj_set_style_pad_all(ginfo.p1_slider, 2, LV_PART_KNOB);lv_obj_set_style_pad_all(ginfo.p2_slider, 2, LV_PART_KNOB);lv_obj_add_event_cb(ginfo.p1_slider, slider_event_cb, LV_EVENT_VALUE_CHANGED, NULL);lv_obj_add_event_cb(ginfo.p2_slider, slider_event_cb, LV_EVENT_VALUE_CHANGED, NULL);lv_obj_set_grid_cell(ginfo.p1_slider, LV_GRID_ALIGN_STRETCH, 1, 1, LV_GRID_ALIGN_START, 1, 1);lv_obj_set_grid_cell(ginfo.p2_slider, LV_GRID_ALIGN_STRETCH, 1, 1, LV_GRID_ALIGN_START, 2, 1);ginfo.run_btn = lv_button_create(par);lv_obj_add_event_cb(ginfo.run_btn, run_button_event_handler, LV_EVENT_CLICKED, NULL);lv_obj_t * btn_label = lv_label_create(ginfo.run_btn);lv_label_set_text(btn_label, LV_SYMBOL_PLAY);lv_obj_center(btn_label);lv_obj_set_grid_cell(ginfo.run_btn, LV_GRID_ALIGN_STRETCH, 2, 1, LV_GRID_ALIGN_STRETCH, 1, 2);ginfo.chart = lv_chart_create(par);lv_obj_set_style_pad_all(ginfo.chart, 0, LV_PART_MAIN);lv_obj_set_style_size(ginfo.chart, 0, 0, LV_PART_INDICATOR);lv_chart_set_type(ginfo.chart, LV_CHART_TYPE_SCATTER);ginfo.ser1 = lv_chart_add_series(ginfo.chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);lv_chart_set_range(ginfo.chart, LV_CHART_AXIS_PRIMARY_Y, 0, 1024);lv_chart_set_range(ginfo.chart, LV_CHART_AXIS_PRIMARY_X, 0, 1024);lv_chart_set_point_count(ginfo.chart, CHART_POINTS_NUM);lv_obj_set_grid_cell(ginfo.chart, LV_GRID_ALIGN_STRETCH, 0, 3, LV_GRID_ALIGN_STRETCH, 3, 1);
}#endif

该示例展示了在动画中使用cubic-bezier3。 贝塞尔曲线3的控制点P1、P2可以通过滑块调整。 图表实时显示三次贝塞尔曲线。 您可以单击运行按钮在cubic-bezier3的当前点查看动画。（感觉显示一段时间的温度变化或者一些指标值变化可以用到）

4、示例4（动画时间轴）

#include "../lv_examples.h"
#if LV_USE_FLEX && LV_BUILD_EXAMPLESstatic const int32_t obj_width = 90;
static const int32_t obj_height = 70;static void set_width(lv_anim_t * var, int32_t v)
{lv_obj_set_width(var->var, v);
}static void set_height(lv_anim_t * var, int32_t v)
{lv_obj_set_height(var->var, v);
}static void set_slider_value(lv_anim_t * var, int32_t v)
{lv_slider_set_value(var->var, v, LV_ANIM_OFF);
}static void btn_start_event_handler(lv_event_t * e)
{lv_obj_t * btn = lv_event_get_current_target_obj(e);lv_anim_timeline_t * anim_timeline = lv_event_get_user_data(e);bool reverse = lv_obj_has_state(btn, LV_STATE_CHECKED);lv_anim_timeline_set_reverse(anim_timeline, reverse);lv_anim_timeline_start(anim_timeline);
}static void btn_pause_event_handler(lv_event_t * e)
{lv_anim_timeline_t * anim_timeline = lv_event_get_user_data(e);lv_anim_timeline_pause(anim_timeline);
}static void slider_prg_event_handler(lv_event_t * e)
{lv_obj_t * slider = lv_event_get_current_target_obj(e);lv_anim_timeline_t * anim_timeline = lv_event_get_user_data(e);int32_t progress = lv_slider_get_value(slider);lv_anim_timeline_set_progress(anim_timeline, progress);
}/*** 创建动画时间轴*/
void lv_example_anim_timeline_1(void)
{/* 创建动画时间线 */lv_anim_timeline_t * anim_timeline = lv_anim_timeline_create();lv_obj_t * par = lv_screen_active();lv_obj_set_flex_flow(par, LV_FLEX_FLOW_ROW);lv_obj_set_flex_align(par, LV_FLEX_ALIGN_SPACE_AROUND, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER);/* 创建 btn_start */lv_obj_t * btn_start = lv_button_create(par);lv_obj_add_event_cb(btn_start, btn_start_event_handler, LV_EVENT_VALUE_CHANGED, anim_timeline);lv_obj_add_flag(btn_start, LV_OBJ_FLAG_IGNORE_LAYOUT);lv_obj_add_flag(btn_start, LV_OBJ_FLAG_CHECKABLE);lv_obj_align(btn_start, LV_ALIGN_TOP_MID, -100, 20);lv_obj_t * label_start = lv_label_create(btn_start);lv_label_set_text(label_start, "Start");lv_obj_center(label_start);/* 创建 btn_pause */lv_obj_t * btn_pause = lv_button_create(par);lv_obj_add_event_cb(btn_pause, btn_pause_event_handler, LV_EVENT_CLICKED, anim_timeline);lv_obj_add_flag(btn_pause, LV_OBJ_FLAG_IGNORE_LAYOUT);lv_obj_align(btn_pause, LV_ALIGN_TOP_MID, 100, 20);lv_obj_t * label_pause = lv_label_create(btn_pause);lv_label_set_text(label_pause, "Pause");lv_obj_center(label_pause);/* 创建slider_prg */lv_obj_t * slider_prg = lv_slider_create(par);lv_obj_add_event_cb(slider_prg, slider_prg_event_handler, LV_EVENT_VALUE_CHANGED, anim_timeline);lv_obj_add_flag(slider_prg, LV_OBJ_FLAG_IGNORE_LAYOUT);lv_obj_align(slider_prg, LV_ALIGN_BOTTOM_MID, 0, -20);lv_slider_set_range(slider_prg, 0, LV_ANIM_TIMELINE_PROGRESS_MAX);/* 创建三个对象 */lv_obj_t * obj1 = lv_obj_create(par);lv_obj_set_size(obj1, obj_width, obj_height);lv_obj_set_scrollbar_mode(obj1, LV_SCROLLBAR_MODE_OFF);lv_obj_t * obj2 = lv_obj_create(par);lv_obj_set_size(obj2, obj_width, obj_height);lv_obj_set_scrollbar_mode(obj2, LV_SCROLLBAR_MODE_OFF);lv_obj_t * obj3 = lv_obj_create(par);lv_obj_set_size(obj3, obj_width, obj_height);lv_obj_set_scrollbar_mode(obj3, LV_SCROLLBAR_MODE_OFF);/* 动画滑块 */lv_anim_t a_slider;lv_anim_init(&a_slider);lv_anim_set_var(&a_slider, slider_prg);lv_anim_set_values(&a_slider, 0, LV_ANIM_TIMELINE_PROGRESS_MAX);lv_anim_set_custom_exec_cb(&a_slider, set_slider_value);lv_anim_set_path_cb(&a_slider, lv_anim_path_linear);lv_anim_set_duration(&a_slider, 700);/* anim-obj1 */lv_anim_t a1;lv_anim_init(&a1);lv_anim_set_var(&a1, obj1);lv_anim_set_values(&a1, 0, obj_width);lv_anim_set_custom_exec_cb(&a1, set_width);lv_anim_set_path_cb(&a1, lv_anim_path_overshoot);lv_anim_set_duration(&a1, 300);lv_anim_t a2;lv_anim_init(&a2);lv_anim_set_var(&a2, obj1);lv_anim_set_values(&a2, 0, obj_height);lv_anim_set_custom_exec_cb(&a2, set_height);lv_anim_set_path_cb(&a2, lv_anim_path_ease_out);lv_anim_set_duration(&a2, 300);/* anim-obj2 */lv_anim_t a3;lv_anim_init(&a3);lv_anim_set_var(&a3, obj2);lv_anim_set_values(&a3, 0, obj_width);lv_anim_set_custom_exec_cb(&a3, set_width);lv_anim_set_path_cb(&a3, lv_anim_path_overshoot);lv_anim_set_duration(&a3, 300);lv_anim_t a4;lv_anim_init(&a4);lv_anim_set_var(&a4, obj2);lv_anim_set_values(&a4, 0, obj_height);lv_anim_set_custom_exec_cb(&a4, set_height);lv_anim_set_path_cb(&a4, lv_anim_path_ease_out);lv_anim_set_duration(&a4, 300);/* anim-obj3 */lv_anim_t a5;lv_anim_init(&a5);lv_anim_set_var(&a5, obj3);lv_anim_set_values(&a5, 0, obj_width);lv_anim_set_custom_exec_cb(&a5, set_width);lv_anim_set_path_cb(&a5, lv_anim_path_overshoot);lv_anim_set_duration(&a5, 300);lv_anim_t a6;lv_anim_init(&a6);lv_anim_set_var(&a6, obj3);lv_anim_set_values(&a6, 0, obj_height);lv_anim_set_custom_exec_cb(&a6, set_height);lv_anim_set_path_cb(&a6, lv_anim_path_ease_out);lv_anim_set_duration(&a6, 300);/* 将动画添加到时间线 */lv_anim_timeline_add(anim_timeline, 0, &a_slider);lv_anim_timeline_add(anim_timeline, 0, &a1);lv_anim_timeline_add(anim_timeline, 0, &a2);lv_anim_timeline_add(anim_timeline, 200, &a3);lv_anim_timeline_add(anim_timeline, 200, &a4);lv_anim_timeline_add(anim_timeline, 400, &a5);lv_anim_timeline_add(anim_timeline, 400, &a6);lv_anim_timeline_set_progress(anim_timeline, LV_ANIM_TIMELINE_PROGRESS_MAX);
}#endif

展示：创建动画时间轴（可以用在下载内容的过程中，比如升级固件或者下载文件，播放歌曲或者视频等过程中）

三、最后

接下来我们了解下事件，基本上动画效果的切换以及前后台的交互都会借助于事件方式来处理。