IOS:UITextField设置背景提示字，左侧图标的方法

   //搜索框背景

        _searchTextField.backgroundColor=kColorFromRGB((0x456C91));

        _searchTextField.placeholder=@"请输入搜索内容";

   //背景提示字的颜色,字体

        [_searchTextField setValue:kColorFromRGB((0x7D98B2)) forKeyPath:@"_placeholderLabel.textColor"];

        [_searchTextField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];

    //搜索图

        UIImageView *searchP=[[UIImageView alloc]initWithFrame:CGRectMake(2, 6, 33, 33)];

        searchP.image=[UIImage imageNamed:@"searchT"];

        _searchTextField.leftView=searchP;

        _searchTextField.leftViewMode=UITextFieldViewModeAlways;

        _searchTextField.contentVerticalAlignment=UIControlContentVerticalAlignmentCenter;

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注意：上面的提示字的颜色设置在13版本系统后会报错，APP用到了会闪退，大家可以搜搜相关内容